Edelbrock Pro Flo 4 and Sanderson BB8 Headers Project

[Beach-Burban]

Sorry in advance for the lenghty rant just to ask one question!

No matter how much effort I put into getting prepped to do a project, something jumps out to derail me a bit...which is to be expected when mixing old with new, I suppose! It took me nearly 10 months to receive my EFI kit, and having done much of the preliminary work, I decided to have headers installed for me at the same time that I was getting the O2 Sensor Bung welded into my exhaust. Before purchasing the BB8's, I followed Sanderson's instructions about verifying that I actually had the original Big Block motor mounts installed...and thanks to Lock Doc's pictorial post, I was able to determine that I did in fact have the "year specific" motor mounts installed under my 454 in the forward position (there are only two positions, right?). My '72 Suburban originally came with a 350 Small Block, but the original owner (who worked for a GMC/Chevrolet truck dealership as Service Manager for over 45 years) used the correct '72 Only Big Block motor mounts when he did the transplant...so I believed I was golden. Not the case when the BB8's install was attempted by my "Header-Pro" and I was quickly called and given the bad news that the passenger side collector was hitting the frame and not allowing the mounting flange to seat against the head (driver side was not even attempted at this point). I did some more research and found an interesting write-up along with some pictures from when Sanderson developed and test fit the BB8's using an original Big Block truck. If I'm not mistaken, the Big Block truck they used was a '68 to '71 version...and they even showed that a cresent shape was ground out for the fittment of the motor mounts??? I'm confused by two things (actually a lot more than two but at this moment, I'll address the two): 1) Does Sanderson know that in '72, GM had a "one year only" motor mount for the Big Block trucks? And 2) Doesn't grinding an area of the frame negate the idea of designing headers that actually fit this application? Both questions are rhetorical, but you get my point, right? Now I have also read that there was a design change early on, so that could explain no longer having to grind the frame...which leads to my actual question to the much more experienced board members: Do the '68 to '71 Big Block motor mounts position the engine higher than the '72 only Big Block motor mounts? A higher fit is what my header-professional said was needed. At this point, I'll have to wait until my EFI is up and running before raising the 454 up (and possibly out) to determine what needs to be done to fit the headers...but I did get the O2 Bung welded in place after the passenger side exhaust manifold was reinstalled. Am I missing something obvious??? I'll add some pictures, but please ask questions if you think I'm overlooking something! Thanks for any thoughts you might have.

Woody


Collector contacting frame.

Gap between flange and head...primary tube contacting motor mount stand.

Passenger side motor mount stand.

Crappy side view picture of motor mount.

Driver side motor mount stand.

[Beach-Burban]

First three photos credit to Lock Doc...Thanks Leon!


Obviously what I have.

Will these raise the engine?

Obviously what I don't have.

Does this spacing appear to be correct for the Big Block?

At least I got my O2 Bung installed!!!

Woody

[Steeveedee]

Lots of troubles, hope they get straightened out. My '70 BB truck has an HEI; the cap is a little over 4" away from the firewall. I have the opposite problem- my fan is very close to the radiator- the front edge is 1-1/2" away. It's always been like that, for the 41 years that I've known this truck. I finally just built a custom shroud for it. I was looking at the Blueprint Engineering 496 stroker, which is based on the 454. I wouldn't be using headers, but your problems give me pause on that kind of purchase.

[Beach-Burban]

Originally Posted by Steeveedee

Lots of troubles, hope they get straightened out. My '70 BB truck has an HEI; the cap is a little over 4" away from the firewall. I have the opposite problem- my fan is very close to the radiator- the front edge is 1-1/2" away. It's always been like that, for the 41 years that I've known this truck. I finally just built a custom shroud for it. I was looking at the Blueprint Engineering 496 stroker, which is based on the 454. I wouldn't be using headers, but your problems give me pause on that kind of purchase.

Our Big Blocks are situated the same then...my HEI is about 4" away from firewall (I guess my picture makes it look closer?) and the front of the fan clutch has about 1 1/2" gap before hitting the radiator. I'm using an original BB fan shroud that fits pretty good but the fan blades come right to the edge without sticking out at all...not ideal from what I'm told? These Sanderson headers are used on a lot of our trucks, but I'm thinking the ''72 only" motor mounts are an issue??? Thanks for the input!

Woody

[Steeveedee]

Originally Posted by Beach-Burban

Our Big Blocks are situated the same then...my HEI is about 4" away from firewall (I guess my picture makes it look closer?) and the front of the fan clutch has about 1 1/2" gap before hitting the radiator. I'm using an original BB fan shroud that fits pretty good but the fan blades come right to the edge without sticking out at all...not ideal from what I'm told? These Sanderson headers are used on a lot of our trucks, but I'm thinking the ''72 only" motor mounts are an issue??? Thanks for the input!

Woody

You must have a different shroud? I'm running the stock short water pump, and the fan was nowhere near close to the edge of the shroud that was in the truck, it stuck way inside. If you have a 454, does it have the short water pump?

[Beach-Burban]

Originally Posted by Steeveedee

You must have a different shroud? I'm running the stock short water pump, and the fan was nowhere near close to the edge of the shroud that was in the truck, it stuck way inside. If you have a 454, does it have the short water pump?

Yes...it is the short water pump. My fan blades are completely inside the shroud but the blade edges are right at the shroud edge??? My mechanic says that's where it's supposed to be for safety reasons, but most on this site say it should be sticking out of the shroud about half way??? After a lot of trial and error, my 454 temperature normally runs between 185/195 in the beach area, but has been known to go to 210/220 in other areas or situations. I've been told that my readings are pretty good for a BB?

Woody

[Steeveedee]

Before I got after the cooling system, my truck would get to 260º, pulling the travel trailer. A BBC will live at those temps, but you're taking its life in your hands. It would also get hot idling. Replaced the fan clutch for the idling, since it's a known good radiator- still runs hot. So why would it run hot with a known good radiator, at speed? The answer was stupid simple. I put a high-flow thermostat in it, and that cured it. This truck has had problems with running hot the entire time I've known it- 41 years! If my FiL stopped for gas, there was going to be at least a half-hour wait until it cooled enough to start again. Some people on here run a BBC without even a shroud, and have no temp problems. :???: Mine never goes over 190º now (180º thermostat) on steep hills, but I have yet to tow the trailer in hot weather because the campgrounds have been closed, and I'm averse to dry camping in the desert. I put a severe duty clutch on it, too. Boy does that thing roar when it gets going!

[Beach-Burban]

Originally Posted by Steeveedee

Before I got after the cooling system, my truck would get to 260º, pulling the travel trailer. A BBC will live at those temps, but you're taking its life in your hands. It would also get hot idling. Replaced the fan clutch for the idling, since it's a known good radiator- still runs hot. So why would it run hot with a known good radiator, at speed? The answer was stupid simple. I put a high-flow thermostat in it, and that cured it. This truck has had problems with running hot the entire time I've known it- 41 years! If my FiL stopped for gas, there was going to be at least a half-hour wait until it cooled enough to start again. Some people on here run a BBC without even a shroud, and have no temp problems. :???: Mine never goes over 190º now (180º thermostat) on steep hills, but I have yet to tow the trailer in hot weather because the campgrounds have been closed, and I'm averse to dry camping in the desert. I put a severe duty clutch on it, too. Boy does that thing roar when it gets going!

Thanks for the tip Steven...I'll have to look into a high flow thermostat! I also have a severe duty clutch but I honestly don't notice any sound difference when it kicks in or out...if mine is working properly? It's fairly new???

Woody

[Steeveedee]

Originally Posted by Beach-Burban

Thanks for the tip Steven...I'll have to look into a high flow thermostat! I also have a severe duty clutch but I honestly don't notice any sound difference when it kicks in or out...if mine is working properly? It's fairly new???

Woody

It may well be that if the fan is too far into the shroud that it won't make a lot of noise? Or maybe what you hear is normal, and I just wasn't getting good coupling, before? I'll take a pic of my setup when it gets light out. FWIW, I'll take the "noise" over running hot.

[Bigdav160]

I never had an original BB truck but I thought the style in your first pic started in '73 models.

I had a 67 that I installed BB on the SBC stands. The headers didn't fit and there was plenty of grinding on the frame and hammer work on the pipes.

In the mid 1980's I wanted to install another BB in a '72 and went to the dealer and purchased the stands you have in the second pic. Yes it moved the engine up and forward.

[SCOTI]

Beach-Burban,

As @Bigdav160 mentioned, the mounts in the first image are what I thought were post-72 mounts & the 2nd image is what I always understood were for 68-72's. They're what I used for my BBC swap in my 67/68 mothballed project. LocDoc knows his history but I researched/learned about the mounts before doing my swap & never was told there was a '72 only' frame stanchion/mount. Interesting to learn this.

Back when I did my BBC swap, Sanderson didn't make the BB8 headers for trucks. I used the BB3's for 68-72 Chevelles. I had to trim minimal amount from the edge of the frame rail (~.1875-.250"?) where the collector is located. I just wanted to share what I did.

[Beach-Burban]

Originally Posted by Steeveedee

It may well be that if the fan is too far into the shroud that it won't make a lot of noise? Or maybe what you hear is normal, and I just wasn't getting good coupling, before? I'll take a pic of my setup when it gets light out. FWIW, I'll take the "noise" over running hot.

I agree Steven...noisey over running hot is better! I'm no expert by any means...it could just be my bad ears don't pick up the change???

Woody

[Beach-Burban]

Originally Posted by Bigdav160

I never had an original BB truck but I thought the style in your first pic started in '73 models.

I had a 67 that I installed BB on the SBC stands. The headers didn't fit and there was plenty of grinding on the frame and hammer work on the pipes.

In the mid 1980's I wanted to install another BB in a '72 and went to the dealer and purchased the stands you have in the second pic. Yes it moved the engine up and forward.

Bigdav...I saw pictures of '73 to '87 mounts in another thread, and I'm pretty sure they were different than what Lock Doc has listed as '72 BB only, but of course I can't really see 100% of my mounts while they are installed?

Believe me...I'm no expert with regards to any of this, but I also read that because a BB wasn't available until sometime in '68, '67 frames need a lot of work when swaping in a BB with headers no matter which mounts you use?

So they sold you '68 to '71 mounts for a '72...that's interesting! I wonder if they knew that you would have less issues with the older mounts? Exactly my question!

Thanks Bigdav...I really appreciate your input!

Woody

[Beach-Burban]

Originally Posted by SCOTI

Beach-Burban,

As @Bigdav160 mentioned, the mounts in the first image are what I thought were post-72 mounts & the 2nd image is what I always understood were for 68-72's. They're what I used for my BBC swap in my 67/68 mothballed project. LocDoc knows his history but I researched/learned about the mounts before doing my swap & never was told there was a '72 only' frame stanchion/mount. Interesting to learn this.

Back when I did my BBC swap, Sanderson didn't make the BB8 headers for trucks. I used the BB3's for 68-72 Chevelles. I had to trim minimal amount from the edge of the frame rail (~.1875-.250"?) where the collector is located. I just wanted to share what I did.

Thanks for responding SCOTI...I found it interesting as well! I've read posts from others that seem to confirm the "72 only" mounts that Lock Doc photographed.

I've heard that the BB3's would work, but I went with the BB8's as they are made for our application...and should not have been an issue at all!!! I am curious if the 67/68 BB project of yours used a 67 or 68 frame? If 68, I understand the minimal trimming due to using BB3's...but if you used a 67 frame, I would have thought that a tremendous amount of work would have been required? I've said it many times...I'm no expert (unless asking questions is an art form).

Thanks again!

Woody

[SCOTI]

Originally Posted by Beach-Burban

Thanks for responding SCOTI...I found it interesting as well! I've read posts from others that seem to confirm the "72 only" mounts that Lock Doc photographed.

I've heard that the BB3's would work, but I went with the BB8's as they are made for our application...and should not have been an issue at all!!! I am curious if the 67/68 BB project of yours used a 67 or 68 frame? If 68, I understand the minimal trimming due to using BB3's...but if you used a 67 frame, I would have thought that a tremendous amount of work would have been required? I've said it many times...I'm no expert (unless asking questions is an art form).

Thanks again!

Woody

68 frame

[Beach-Burban]

Originally Posted by SCOTI

68 frame

Got it SCOTI...thanks for the response!

Woody

[KQQL IT]

Those 72 only look an awful lot like squarebody stuff.

I thought our 68 was on squarebody mounts, but maybe they're 72 mounts.

[Beach-Burban]

Originally Posted by KQQL IT

Those 72 only look an awful lot like squarebody stuff.

I thought our 68 was on squarebody mounts, but maybe they're 72 mounts.

It's confusing to me too, KQQL IT...but I had seen some 73 and up motor mount pictures in another post, and they were similar but not the same. I guess it makes sense that if they figured out there was an issue with the 72 mounts and changed them in 73, that GM might only slightly change the design??? I'm now wondering if the part of the motor mount that I can't see is part of the problem? Anyone know if there is a way to raise the engine by changing the "engine mount" side and keep the stands (?perches?)???

Woody

[SCOTI]

Originally Posted by Beach-Burban

It's confusing to me too, KQQL IT...but I had seen some 73 and up motor mount pictures in another post, and they were similar but not the same. I guess it makes sense that if they figured out there was an issue with the 72 mounts and changed them in 73, that GM might only slightly change the design??? I'm now wondering if the part of the motor mount that I can't see is part of the problem? Anyone know if there is a way to raise the engine by changing the "engine mount" side and keep the stands (?perches?)???

Woody

Again, my first suggestion would be to simply trim the frame rail.
Beyond that, what about making some flat spacers that can be inserted between the MM pad & block?

[Southcity]

Originally Posted by Steeveedee

So why would it run hot with a known good radiator, at speed? The answer was stupid simple. I put a high-flow thermostat in it, and that cured it.

Can you please share which brand/part# of high flow thermostat you ended up using? Thanks

[Steeveedee]

Originally Posted by Southcity

Can you please share which brand/part# of high flow thermostat you ended up using? Thanks

It's a Stant, but I don't recall the number. I got it at NAPA. The real tell is that the ring where it sits in the manifold isn't very wide- the hole is bigger than a standard thermostat.

[KQQL IT]

Originally Posted by Beach-Burban

It's confusing to me too, KQQL IT...but I had seen some 73 and up motor mount pictures in another post, and they were similar but not the same. I guess it makes sense that if they figured out there was an issue with the 72 mounts and changed them in 73, that GM might only slightly change the design??? I'm now wondering if the part of the motor mount that I can't see is part of the problem? Anyone know if there is a way to raise the engine by changing the "engine mount" side and keep the stands (?perches?)???

Woody

I looked at our 68 with thorley tri Ys yesterday.
There's some hackery on the driver's side rail..

[Beach-Burban]

Originally Posted by SCOTI

Again, my first suggestion would be to simply trim the frame rail.
Beyond that, what about making some flat spacers that can be inserted between the MM pad & block?

From what my header guy showed me, the collector would clear if enginge was higher then header would be in the right position to mate with the head? The picture doesn't depict what is happening to well but the front primary tube on passenger side is hitting the bolting flange of the motor mount stand.

Spacers aren't a bad idea, but that seem like it would take about the same amount of work as replacing with the proper mounts? Thanks again.

Woody

[Beach-Burban]

Originally Posted by KQQL IT

I looked at our 68 with thorley tri Ys yesterday.
There's some hackery on the driver's side rail..

I can see that, KQQL IT...exactly what I'm trying to avoid! The squarebody mounts are supposed to be a better fit for headers and I read that those tri Y's were the easiest fitting full length headers, so maybe you do have '72 mounts under there? Thanks again.

Woody

[SCOTI]

Originally Posted by Beach-Burban

From what my header guy showed me, the collector would clear if enginge was higher then header would be in the right position to mate with the head? The picture doesn't depict what is happening to well but the front primary tube on passenger side is hitting the bolting flange of the motor mount stand.

Spacers aren't a bad idea, but that seem like it would take about the same amount of work as replacing with the proper mounts? Thanks again.

Woody

I wouldn't argue your point if you could define what the 'proper' mount actually is. I guess what I'm trying to communicate is are you 101% sure if you get the different set of motor mount stanchions that things will fit w/o issue? I'm betting 'no' or else this discussion wouldn't be happening.

If you're not sure the mounts (stanchions) are the Golden Ticket you seek, you're still potentially stuck. To me, that would be frustrating. Say the 'new/different' stanchions allow the headers to fit but now the fan doesn't line-up or a valve cover interferes w/something (common issues when using different parts). Thus my suggestion of tweaking things to work w/what you have since the drivetrain is already installed/in-place.

I get it if you don't wish to go that route. If someone had both types & would let you try the set-up that's pre-73 big-block (but different from yours) to see if that solves the issue, that's 100% how I would go about it first. Barring that and/or wanting to move forward sooner than later, I'd tweak things.

I wish I could help & will definitely be watching to see what the answer is to your dilemma.