The Journey That Is My 1972 C20 BBC Highlander - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67RS/SSx2 · 09-13-2021, 10:03 PM

Thought I would start a thread to follow the work on my new, old truck. I am not a mechanic, nor am I a paint-and-body guy. So I will not be doing any extraordinary tasks with this truck. If its needs go beyond my abilities I will involve friends who are in those fields.

The goal is to keep it as original as possible but to keep it very usable as a truck. I will replace with new where necessary, just want to stay as true as possible to original.

So I got the truck home about a week ago. Turns out it had a gas leak on the carburetor (another thread). That was pretty straightforward to remedy. Now done.

Truck has a factory aux tank. Trying to figure out the gauge/tank thing so I added fuel to each tank and watched the gauge. Immediate problem appeared. Aux tank has a pretty good leak. Was quite the circus to get it home and try to capture as much leaking fuel as possible.

So now I need to drop the aux tank to evaluate. I think the way GM designed to bolts/nuts to secure the aux tank is pretty ingenius. Managed to get two of the bolts out with little difficulty (Kroil is my friend). Third one stripped the 3/8" ratchet opening as I tried to loosen it. I'll have to find a way to get that one out. Later I can have a machine shop build a similar replacement for the stripped one.

The filler cover for the aux tank was full of debris (leaves, etc). I managed to get it off, cleaned out the debris, and now have to figure out how to remove the very rusty plate that goes between the tank and filler neck. Not sure how I am going to get that off.

Also need to drop the tank because I plan to have a spray-in bedliner installed. The guy I use (for my last 4 or 5 trucks) does an excellent job. He spray Bullet liner and said he can color match the truck's color. I like that idea.

He said he will have the bed blasted (dustless blasting) which will even remove the seam sealer. Then he will shoot the bedliner. Quoted a fair price so I think this is the route I am going. Just have to conquer the aux tank first!

I know everyone likes pics so...

**HO455** · 09-14-2021, 03:43 PM

Looking forward to more. You pictures sparked a question and there is no real reason I need to know this other than me being nosey.
Are your auxiliary tank vents tied into the emissions evap system?

67RS/SSx2 · 09-14-2021, 10:45 PM

Only have one aux tank, the factory aux tank option. You might be able to make out the vent line from the aux tank in the pic. It connects high in the filler tube. The filler tube is double wall at the top with the vent connecting to the outer tube.

Whether that is the only vent I do not know. Will find out when I finally drop the aux tank where I can see the top of the tank where the vent connects. Have to figure out how to conquer the rust for that to happen.

**knuckle-nurse** · 09-15-2021, 12:02 PM

I'm restoring a 72 C20 BB Cheyenne that has the aux tank like yours. I removed the tank last week. I cut all the fuel lines under the truck, removed the fender mount bolt, zip cut the clamps on the fill and vent hoses, used a box cutter to slice and remove the hoses. The 2 screws holding the fill/vent plate to the bed would not come out so I cut the heads. The 3 special carriage mount nuts under the tank were rusted solid to the bolts so I supported the tank with a floor jack and a piece of plywood and zip cut the top of the heads off the carriage bolts. I then lowered the tank out of the truck. The filler and vent pipes that are part of the tank will slide out of their holes in the bed.
My tank is too rusty to save so I'm getting a local fab guy to replicate it.
Need to find a sender unit that will work.
If you get the nuts machined I'm in for 3.

67RS/SSx2 · 09-15-2021, 09:01 PM

Quote:

Originally Posted by knuckle-nurse

removed the fender mount bolt, zip cut the clamps on the fill and vent hoses, If you get the nuts machined I'm in for 3.

I overlooked the bolt that attaches the tank to the lower bedside. Thanks, now I know it has to come out too.

I do not understand what you mean by "zip cut". Is that using something like a cutoff wheel or a thin stone on an angle grinder?

I will update this thread with my solution to the rusted out special nut used on the three large bolts. I have a few ideas that may keep me away from the machine shop. I'm cheap when it is practical!

**knuckle-nurse** · 09-15-2021, 11:44 PM

I use an small air powered tool with a cut off disc. We call it zip cutting.
I'm hoping to find or replicate the nuts as I want this truck all original.
Thanks...Scott

67RS/SSx2 · 09-18-2021, 09:58 PM

Well...more bad news. I used a flashlight to look into the in-cab tank to see how much fuel was in it. I have had the valve turned to the aux tank to try to empty it so I can drop it with less weight.

The in-cab tank is not more than 1/4 full. Hmmm? I surmise that the valve is not switching between tanks but that both tanks are active at the same time. The gauge has not changed since I brought the truck home so it is not functioning properly either.

I filled the in-cab tank to the brim a week or so ago. I also added fuel to the aux tank but not very much. Then I noticed the leak from the aux tank. It seemed to leak a lot but I have no way of knowing how much. I think fuel from the in-cab tank was moving to the aux tank as that tank leaked. Since the in-cab tank is higher, much of the fuel from that tank made its way into the aux tank and leaked out.

I am confident both tanks are low so now is probably a good time to drop the aux tank. I will have to pinch off the lines to minimize leakage while the aux tank is out. If I can manage, I will remove the switching valve also to test it. It is an electric valve likely from a newer model. The manual switchover vale is no longer in place.

Half a step forward, six steps backwards!

**knuckle-nurse** · 09-18-2021, 10:30 PM

Do yourself a favor and get a cheap 12 volt universal fuel pump and a length of fuel hose. Stick the hose down the filler tube to the bottom of the tank, hook it up to a car battery and pump out all the fuel from both tanks

**knuckle-nurse** · 09-18-2021, 10:52 PM

I'm assuming you tried to remove the drain plug from the aux. tank and it didn't want to come.
Can you measure the overall length of the carriage bolts for me? My bolts and nuts are a rusty/siezed mess and as mentioned had to cut the bolts to remove the tank.
Thanks...Scott

67RS/SSx2 · 09-19-2021, 05:58 PM

I have two fuel siphoning systems new in the box. One has a siphon bulb. The other has a siphon hand pump. Bought them from O'Reillys or Autozone, can't remember which. Neither of them work. Argggg! Neither will pull fuel up into the hose even when I know the hose is submerged in the fuel. Oh well.

I currently am soaking the aux tank drain plug in Kroil. Not in a hurry. Will probably give it a few days to creep up the threads then give it a try. Is the plug a hex key plug? It's a little too low for me to get under and see.

My plan is to put the truck on jack stands to gain a little room under it. I am neither young nor skinny so I need all the room I can get.

As for the carriage bolts. They are 7/16" 14 tpi and 12" long. There is a little bit of an angle on the picture. The bolt is exactly 12" long. Hope this helps.

67RS/SSx2 · 09-19-2021, 06:07 PM

This is the electric switchover valve someone added. It has six hoses connected to it. I would guess three hoses to be 3/8" and the other three to be 5/16".

The valve clicks when I apply 12VDC so it is likely working. I will completely bypass it and test it to make sure.

One hose sends fuel to the fuel pump from a tank. One hose brings fuel from the in-cab tank to the switchover valve, and the final (large) hose brings fuel from the aux tank to the switchover valve. Do I have that right? Are the three smaller hoses for unused fuel return? Does anyone recognize this valve (what it is from)?

Lots to learn!

67RS/SSx2 · 09-19-2021, 06:14 PM

Also, any recommendations for fuel line (hose). Wow, that stuff has gotten expensive.

**knuckle-nurse** · 09-20-2021, 02:40 PM

That drain plug is a hex. I have yet to figures out all my fuel and vent lines. I would buy a good quality rubber fuel line (Gates etc) its cheaper to buy it by the roll if you need a lot. Thanks for measuring the bolts. Did you figure out what you are going to do to replace that large mount nut? I sent you a pm.

67RS/SSx2 · 10-04-2021, 10:31 PM

Stripped out the drain plug, just too rusted even after soaking. Drilled it out and let the tank empty through that hole. Think I got 15-18 gallons out of it. Clearly the in-cab tank drained/siphoned into the aux tank.

Rubber fuel hoses were trash. I think that is where my fuel leak was. Was able to drop the aux tank after grinding the head off the final bolt. Just could not break that last "special nut" loose.

The aux tank "appears" to be solid but a bit dirty. Plan is to see if a radiator shop can clean it up. Hard to find a good radiator shop nowadays though.

Removed the switchover valve as well. I will test it to see if it is switching properly. Connected the in-cab tank to the lines leading to the fuel pump. Afterwards, cranked and cranked and cranked but could not get it to pick up fuel. Used what was left in my starter fluid can then primed with gas but no luck. Guess I will pull the fuel line at the fuel pump and see if fuel will gravity feed to that point. Then try it again.

Progress...just not as much as I would like.

MARKDTN · 10-06-2021, 11:35 AM

That valve looks like a square body style valve. ACDelco 467513. There are 3 port versions for fuel pumps without returns and 6 port versions for pumps with return. Looks like the 6 port versions with single wire are no longer available though. A later 6-port version is available but will require re-wiring.

https://www.rvpartscountry.com/Motor...Valve-Kit.html

Or just go to a manual style 6-port valve like a Groco Fv-65038.

My question is do you really want to use the aux tank? If you don't drive it a lot then the fuel gets old fast. On my '83 K20 I used to have dual tanks but honestly even road miles I need to stop long before I run out of fuel. If you don't need or or just want it to look correct it will be a whole lot easier to make the main tank work.

67RS/SSx2 · 10-06-2021, 09:59 PM

Quote:

Originally Posted by MARKDTN

That valve looks like a square body style valve. ACDelco 467513. There are 3 port versions for fuel pumps without returns and 6 port versions for pumps with return. Looks like the 6 port versions with single wire are no longer available though. A later 6-port version is available but will require re-wiring.

https://www.rvpartscountry.com/Motor...Valve-Kit.html

Or just go to a manual style 6-port valve like a Groco Fv-65038.

My question is do you really want to use the aux tank? If you don't drive it a lot then the fuel gets old fast. On my '83 K20 I used to have dual tanks but honestly even road miles I need to stop long before I run out of fuel. If you don't need or or just want it to look correct it will be a whole lot easier to make the main tank work.

Thanks for the leads on fuel switchover valves. The electric would be much easier to switchover while driving and the truck is set up for that so that is probably what I will do. Although the Groco valves looks interesting (not to mention EXPENSIVE). Mounting it would take a little thought/modification

Do I need the aux tank? Absolutely not! However it is a bit unusual and I like unusual things. So I will give it the old American try to get it back in operation. I think I can. If not, at least I gave it a good shot. My Camaros don't get driven much anymore either. They are a little too pampered.

But I have not had any fuel go bad in them (fingers crossed).

The great news is that the truck is running again! Yipee!!! I let it sit since Sunday. I suspect the heavier fuel displaced the air in the lines due to gravity and when I primed in a bit tonight it finally picked up gas to the pump.

While playing with it in the dark tonight I noticed a couple of things. First, the water pump has GM cast into its housing. Could this be the original water pump? Pretty cool in any case.

Also, I saw an old thread on here that said a Highlander came stock with chrome hub caps. Mine currently has three white painted hub caps (need to find a fourth for now). I thought those were original, or at least stock. What should it have to be stock? The SPID does not mention wheel covers.

Lastly, my stock AM radio arrived today. I am stoked to take out the aftermarket AM/FM and get this one in. She's a beauty too.

**jocko** · 10-07-2021, 12:37 AM

Quote:

Originally Posted by 67RS/SSx2

Also, I saw an old thread on here that said a Highlander came stock with chrome hub caps. Mine currently has three white painted hub caps (need to find a fourth for now). I thought those were original, or at least stock. What should it have to be stock? The SPID does not mention wheel covers.

If your SPID doesn't list RPO PO3 (Chrome Hub Caps), then I'm gonna go out on a limb and assume it also doesn't list YG6,7, or 8 - can you confirm?

The Highlander plaid seat cover could end up on a truck two separate ways - either as a standalone trim option (which will show up on your SPID as 613, 618, etc to inform the color of plaid ordered - sometimes just called "custom" trim too) or as part of the 3 levels of Special Promotional Packages, YG6,7 or 8.

If ordered as a standalone trim option, then the base white hubcaps would have been on the truck originally (unless PO3s were also ordered separately).

If ordered as a Special Promo Pkg, then PO3s were included automatically - and would still show up on the SPID as RPO PO3.

Not applicable to your truck, but on a 1/2 ton, the same holds true except the PO3s were replaced by PA1s (Monte Carlo full wheel covers) when a Special Promo Pkg was the avenue to a plaid seat.

Bottom line - if your truck does not have PO3 on its SPID, it would have been delivered with white hub caps (note that all of the above discussion applies only to a Custom Deluxe trim level trucks - plaid not available on any other trim level, nor were the promo pkgs (Blazers were different)).

67RS/SSx2 · 10-07-2021, 10:36 PM

Thanks Jocko. Your input is spot on. My truck is not a Special Promotion truck, it does not have the YG6, 7, or 8 package.

It is a Z62 CUSTOM DELUXE EQUIP and came with the 611 BLUE PLAID BNCH TRIM. It does not have the PO3 chrome hub caps listed. All of this is according to the SPID. So the white hub caps are correct. That is good to know. Now I just have to find a fourth one and freshen them up, along with the wheels, to look better.

Or if I come across a decent set of chrome hub caps I guess I could go that route. It just would not be correct for this truck. All hub caps for 16.5" wheels are probably hard to find. But the chase is part of the fun!

**jocko** · 10-07-2021, 11:20 PM

You're welcome. For what it's worth, any 69-75 base white hub cap for a 3/4 ton or 1 ton will fit the 16.5" wheels (or the later 16" wheels). The ochre bow tie of the 73-75 caps can be painted Krylon True Blue for a very close match to the original color of the 69-72 blue bow tie.

09-13-2021, 10:03 PM	#1
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	The Journey That Is My 1972 C20 BBC Highlander Thought I would start a thread to follow the work on my new, old truck. I am not a mechanic, nor am I a paint-and-body guy. So I will not be doing any extraordinary tasks with this truck. If its needs go beyond my abilities I will involve friends who are in those fields. The goal is to keep it as original as possible but to keep it very usable as a truck. I will replace with new where necessary, just want to stay as true as possible to original. So I got the truck home about a week ago. Turns out it had a gas leak on the carburetor (another thread). That was pretty straightforward to remedy. Now done. Truck has a factory aux tank. Trying to figure out the gauge/tank thing so I added fuel to each tank and watched the gauge. Immediate problem appeared. Aux tank has a pretty good leak. Was quite the circus to get it home and try to capture as much leaking fuel as possible. So now I need to drop the aux tank to evaluate. I think the way GM designed to bolts/nuts to secure the aux tank is pretty ingenius. Managed to get two of the bolts out with little difficulty (Kroil is my friend). Third one stripped the 3/8" ratchet opening as I tried to loosen it. I'll have to find a way to get that one out. Later I can have a machine shop build a similar replacement for the stripped one. The filler cover for the aux tank was full of debris (leaves, etc). I managed to get it off, cleaned out the debris, and now have to figure out how to remove the very rusty plate that goes between the tank and filler neck. Not sure how I am going to get that off. Also need to drop the tank because I plan to have a spray-in bedliner installed. The guy I use (for my last 4 or 5 trucks) does an excellent job. He spray Bullet liner and said he can color match the truck's color. I like that idea. He said he will have the bed blasted (dustless blasting) which will even remove the seam sealer. Then he will shoot the bedliner. Quoted a fair price so I think this is the route I am going. Just have to conquer the aux tank first! I know everyone likes pics so... Attached Images __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)

09-14-2021, 03:43 PM	#2
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 10,804	Re: The Journey That Is My 1972 C20 BBC Highlander Looking forward to more. You pictures sparked a question and there is no real reason I need to know this other than me being nosey. Are your auxiliary tank vents tied into the emissions evap system? __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

09-14-2021, 10:45 PM	#3
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander Only have one aux tank, the factory aux tank option. You might be able to make out the vent line from the aux tank in the pic. It connects high in the filler tube. The filler tube is double wall at the top with the vent connecting to the outer tube. Whether that is the only vent I do not know. Will find out when I finally drop the aux tank where I can see the top of the tank where the vent connects. Have to figure out how to conquer the rust for that to happen. __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)

09-15-2021, 12:02 PM	#4
knuckle-nurse Senior Member Join Date: Jan 2009 Location: Tugaske SK Canada Posts: 286	Re: The Journey That Is My 1972 C20 BBC Highlander I'm restoring a 72 C20 BB Cheyenne that has the aux tank like yours. I removed the tank last week. I cut all the fuel lines under the truck, removed the fender mount bolt, zip cut the clamps on the fill and vent hoses, used a box cutter to slice and remove the hoses. The 2 screws holding the fill/vent plate to the bed would not come out so I cut the heads. The 3 special carriage mount nuts under the tank were rusted solid to the bolts so I supported the tank with a floor jack and a piece of plywood and zip cut the top of the heads off the carriage bolts. I then lowered the tank out of the truck. The filler and vent pipes that are part of the tank will slide out of their holes in the bed. My tank is too rusty to save so I'm getting a local fab guy to replicate it. Need to find a sender unit that will work. If you get the nuts machined I'm in for 3.

09-15-2021, 11:44 PM	#6
knuckle-nurse Senior Member Join Date: Jan 2009 Location: Tugaske SK Canada Posts: 286	Re: The Journey That Is My 1972 C20 BBC Highlander I use an small air powered tool with a cut off disc. We call it zip cutting. I'm hoping to find or replicate the nuts as I want this truck all original. Thanks...Scott

09-18-2021, 09:58 PM	#7
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander Well...more bad news. I used a flashlight to look into the in-cab tank to see how much fuel was in it. I have had the valve turned to the aux tank to try to empty it so I can drop it with less weight. The in-cab tank is not more than 1/4 full. Hmmm? I surmise that the valve is not switching between tanks but that both tanks are active at the same time. The gauge has not changed since I brought the truck home so it is not functioning properly either. I filled the in-cab tank to the brim a week or so ago. I also added fuel to the aux tank but not very much. Then I noticed the leak from the aux tank. It seemed to leak a lot but I have no way of knowing how much. I think fuel from the in-cab tank was moving to the aux tank as that tank leaked. Since the in-cab tank is higher, much of the fuel from that tank made its way into the aux tank and leaked out. I am confident both tanks are low so now is probably a good time to drop the aux tank. I will have to pinch off the lines to minimize leakage while the aux tank is out. If I can manage, I will remove the switching valve also to test it. It is an electric valve likely from a newer model. The manual switchover vale is no longer in place. Half a step forward, six steps backwards! __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)

09-18-2021, 10:30 PM	#8
knuckle-nurse Senior Member Join Date: Jan 2009 Location: Tugaske SK Canada Posts: 286	Re: The Journey That Is My 1972 C20 BBC Highlander Do yourself a favor and get a cheap 12 volt universal fuel pump and a length of fuel hose. Stick the hose down the filler tube to the bottom of the tank, hook it up to a car battery and pump out all the fuel from both tanks

09-18-2021, 10:52 PM	#9
knuckle-nurse Senior Member Join Date: Jan 2009 Location: Tugaske SK Canada Posts: 286	Re: The Journey That Is My 1972 C20 BBC Highlander I'm assuming you tried to remove the drain plug from the aux. tank and it didn't want to come. Can you measure the overall length of the carriage bolts for me? My bolts and nuts are a rusty/siezed mess and as mentioned had to cut the bolts to remove the tank. Thanks...Scott

09-19-2021, 05:58 PM	#10
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander I have two fuel siphoning systems new in the box. One has a siphon bulb. The other has a siphon hand pump. Bought them from O'Reillys or Autozone, can't remember which. Neither of them work. Argggg! Neither will pull fuel up into the hose even when I know the hose is submerged in the fuel. Oh well. I currently am soaking the aux tank drain plug in Kroil. Not in a hurry. Will probably give it a few days to creep up the threads then give it a try. Is the plug a hex key plug? It's a little too low for me to get under and see. My plan is to put the truck on jack stands to gain a little room under it. I am neither young nor skinny so I need all the room I can get. As for the carriage bolts. They are 7/16" 14 tpi and 12" long. There is a little bit of an angle on the picture. The bolt is exactly 12" long. Hope this helps. Attached Images __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it) Last edited by 67RS/SSx2; 09-19-2021 at 06:08 PM.

09-19-2021, 06:07 PM	#11
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander This is the electric switchover valve someone added. It has six hoses connected to it. I would guess three hoses to be 3/8" and the other three to be 5/16". The valve clicks when I apply 12VDC so it is likely working. I will completely bypass it and test it to make sure. One hose sends fuel to the fuel pump from a tank. One hose brings fuel from the in-cab tank to the switchover valve, and the final (large) hose brings fuel from the aux tank to the switchover valve. Do I have that right? Are the three smaller hoses for unused fuel return? Does anyone recognize this valve (what it is from)? Lots to learn! Attached Images __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)

09-19-2021, 06:14 PM	#12
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander Also, any recommendations for fuel line (hose). Wow, that stuff has gotten expensive. __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)

09-20-2021, 02:40 PM	#13
knuckle-nurse Senior Member Join Date: Jan 2009 Location: Tugaske SK Canada Posts: 286	Re: The Journey That Is My 1972 C20 BBC Highlander That drain plug is a hex. I have yet to figures out all my fuel and vent lines. I would buy a good quality rubber fuel line (Gates etc) its cheaper to buy it by the roll if you need a lot. Thanks for measuring the bolts. Did you figure out what you are going to do to replace that large mount nut? I sent you a pm.

10-04-2021, 10:31 PM	#14
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander Stripped out the drain plug, just too rusted even after soaking. Drilled it out and let the tank empty through that hole. Think I got 15-18 gallons out of it. Clearly the in-cab tank drained/siphoned into the aux tank. Rubber fuel hoses were trash. I think that is where my fuel leak was. Was able to drop the aux tank after grinding the head off the final bolt. Just could not break that last "special nut" loose. The aux tank "appears" to be solid but a bit dirty. Plan is to see if a radiator shop can clean it up. Hard to find a good radiator shop nowadays though. Removed the switchover valve as well. I will test it to see if it is switching properly. Connected the in-cab tank to the lines leading to the fuel pump. Afterwards, cranked and cranked and cranked but could not get it to pick up fuel. Used what was left in my starter fluid can then primed with gas but no luck. Guess I will pull the fuel line at the fuel pump and see if fuel will gravity feed to that point. Then try it again. Progress...just not as much as I would like. __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)

10-06-2021, 11:35 AM	#15
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,131	Re: The Journey That Is My 1972 C20 BBC Highlander That valve looks like a square body style valve. ACDelco 467513. There are 3 port versions for fuel pumps without returns and 6 port versions for pumps with return. Looks like the 6 port versions with single wire are no longer available though. A later 6-port version is available but will require re-wiring. https://www.rvpartscountry.com/Motor...Valve-Kit.html Or just go to a manual style 6-port valve like a Groco Fv-65038. My question is do you really want to use the aux tank? If you don't drive it a lot then the fuel gets old fast. On my '83 K20 I used to have dual tanks but honestly even road miles I need to stop long before I run out of fuel. If you don't need or or just want it to look correct it will be a whole lot easier to make the main tank work. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

10-07-2021, 10:36 PM	#18
67RS/SSx2 Registered User Join Date: Sep 2010 Location: Central Oklahoma Posts: 252	Re: The Journey That Is My 1972 C20 BBC Highlander Thanks Jocko. Your input is spot on. My truck is not a Special Promotion truck, it does not have the YG6, 7, or 8 package. It is a Z62 CUSTOM DELUXE EQUIP and came with the 611 BLUE PLAID BNCH TRIM. It does not have the PO3 chrome hub caps listed. All of this is according to the SPID. So the white hub caps are correct. That is good to know. Now I just have to find a fourth one and freshen them up, along with the wheels, to look better. Or if I come across a decent set of chrome hub caps I guess I could go that route. It just would not be correct for this truck. All hub caps for 16.5" wheels are probably hard to find. But the chase is part of the fun! __________________ 1972 C20 402/TH400/3.54 Highlander 1969 Camaro RS with SS trim, 1967 Camaro RS/SS (sold) 1983 GMC Sierra Classic 2500 crew cab (sold) 1972 Chevy C10 Cheyenne Super (sold) 1984 Chevy Silverado C20 crew cab (bought new by my uncle, in the family until I sold it)



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10-07-2021, 11:20 PM	#19
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,934	Re: The Journey That Is My 1972 C20 BBC Highlander You're welcome. For what it's worth, any 69-75 base white hub cap for a 3/4 ton or 1 ton will fit the 16.5" wheels (or the later 16" wheels). The ochre bow tie of the 73-75 caps can be painted Krylon True Blue for a very close match to the original color of the 69-72 blue bow tie.

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