Lucy gets a modern powerplant

[LooseyLucy71]

Hey Guys,

I've been poking around on the site for a while but just got around to actually joining! I'm in the parts collecting stage of swapping an early 2000's 5.3l truck motor into my 71 C10 (SWB, FS), Lucy. I have the motor, TBSS manifolds, and a few other parts so far. The new motor will be replacing a '75 454 truck motor and will be mating to the original TH400. I'm hoping to pull the big block out in a few weeks and have been doing quite a bit of research. Has anybody else done this swap and kept the TH400? I'm wondering what mounts to use. It seems like people are really happy with the CPP sheet metal mounts, I'm just not sure what combination of mounts and plates to get to leave the trans where sits. Any input is much appreciated.

Thanks,
Andrew

[michael bustamante]

love the screen name man!!
I am doing the same conversion myself but with the mated 4l60
subbed

[LooseyLucy71]

Originally Posted by michael bustamante

love the screen name man!!
I am doing the same conversion myself but with the mated 4l60
subbed

Thanks! I'm only sticking with the TH400 until funds allow.... There's plans to add a 3rd pedal eventually...

[LooseyLucy71]

My internet service isn't great but I'll try to post a few pictures:

[CUSTOM/10]

Can't help with your question, but..... To the best 67-72 chevy truck site there is!!!

Also howdy from another So. NH member !

Gary

[Boog]

Good looking truck. And boat. Wooden?

[LooseyLucy71]

Originally Posted by CUSTOM/10

Can't help with your question, but..... To the best 67-72 chevy truck site there is!!!

Also howdy from another So. NH member !

Gary

Thanks Gary! Looks like we're neighbors. I'm just to the west of you!

[flashed]

Lucy looks very nice ,got any more pics to share ?

[tommys72]

Nice progress

[LooseyLucy71]

It's been a little while since the last update, so here goes:

1. My motor mount kit showed up and I was able to bolt the motor down solid. Of course, the thread count was different on the bolts, so I actually had to unbolt the top half of the mount (from dirty dingo) from the sliders and swap it for the ones with the new kit. The ones I got with the sliders matched the factory threads, but for whatever reason these were different. For those of you who have used DD sliders, you'll also know I had to trim the passenger side mount to clear the block as was already done with the kit from DD. Not a big deal, but not the "run the two bolts in" job I was expecting.

2. I pulled out the entire fuel system. Upon further inspection, my stock tank looks really good inside and doesn't need to be replaced, but I have a fresh one already, so I'm swapping it anyway. if anybody in New England is looking for a good tank with EEC, let me know.

3. I finished up with my prep and painting on the front end of the frame. Not a fun job at all trying to get all that grease off, but one of my big goals here is to get away from the greasy, drippy everything. I also prepped and painted the firewall. I'm not sure how much of the A/C system I'm going to leave in the engine bay yet. We'll see. I plan to get the system running at some point, but of now it's low on the priority list and well out of the budget. The windows go down, enough said there.

4. More engine cleaning! I pulled the intake off and cleaned the valley out, prepped and painted the pulleys on the accessories (alt., ps) and did a little more with the wire wheel. I now have the accessory bracket bolted up and I should be done with external engine cleaning (finally)!

5. I ordered some parts including a flexible 30" transmission dipstick to mount to the firewall, all my fuel system parts (hopefully), O2 sensors, serpentine belt tensioner, and enough Reckhorn 80mil sound deadening to do the floor, back wall, and firewall inside the cab. This is mostly for the Mrs. as I rather enjoy rolling down the highway next to a barrier and wailing on it, but she would prefer at least the option to have it quieter. I'm sure on the longer rides I have planned I'll appreciate it. With the big block, I couldn't get a long ride in without stopping for gas but I think I should have better range now!

The next steps are to start installing the fuel system, trans dipstick, oil pressure line, and of course, wiring. I'm going to see how much wiring I can do with the front clip off as it's much easier to work on everything when you can stand between the engine and the front wheels. I may pull the front bumper and hang inner and outer fenders, but leave the radiator support off for now. Any recommendations on this would be appreciated. Call me crazy, but I'm actually pretty excited about the wiring. Anything but degreasing at this point!

Side note: Found a sweet C60 bucket truck at the junkyard. See pictures below.

[Gainsb]

Nice build so far! Looking forward to hearing the engine fire up!

[BugzC10]

Originally Posted by Gainsb

Nice build so far! Looking forward to hearing the engine fire up!

X2 What's your plans for the C60?

[LooseyLucy71]

Originally Posted by BugzC10

X2 What's your plans for the C60?

I'm certainly looking forward to firing it up as well. No way I can get that c60, but it's probably for sale...

[RustyBucket]

It'll be interesting to see how your 5.3 does on fuel mileage with no O.D. What rear gear ratio is your truck? I have an '02 GMC 6.0 and when I tow I don't use overdrive .... the mileage is UGLY. I know the 6.0 is thirstier than the 5.3 and the '02 truck is heavy. I like the LS motors but wonder if the better economy isn't due a lot to computer engine management and overdrive. I have a mild 454/TKO500 combination in my Blazer. It'll give a little better than 15mpg at a steady 75mph... OR ... you can blast it around in the lower gears and get 7 or 8, but it's a lot more fun.
Please keep posting on your project, enjoying your progress.

[LooseyLucy71]

Originally Posted by RustyBucket

It'll be interesting to see how your 5.3 does on fuel mileage with no O.D. What rear gear ratio is your truck? I have an '02 GMC 6.0 and when I tow I don't use overdrive .... the mileage is UGLY. I know the 6.0 is thirstier than the 5.3 and the '02 truck is heavy. I like the LS motors but wonder if the better economy isn't due a lot to computer engine management and overdrive. I have a mild 454/TKO500 combination in my Blazer. It'll give a little better than 15mpg at a steady 75mph... OR ... you can blast it around in the lower gears and get 7 or 8, but it's a lot more fun.
Please keep posting on your project, enjoying your progress.

I have 3.08s out back. As I probably mentioned earlier the next big step after swapping the 5.3 in is to change the TH400 out for an NV4500. When I installed the posi I put the 3.08s in to give me around 2,000 RPM with the NV4500 at 75, which is about where my 04 with the 4L60 will run down the highway in OD. I'll definitely be tracking mileage both ripping around town and cruising the highway. Definitely looking forward to getting her running soon!

[LooseyLucy71]

I've been picking away at little stuff recently. Got the plates that hold the ignition coils cleaned and painted and installed a new serpentine belt tensioner. Nothing terribly exciting, but it's progress! Today's battle was with removing the original throttle cable. Anybody care to enlighten me on the trick to getting it to come out of the firewall? That would be awesome!

[Boog]

You go inside and squeeze the cable housing with a pair of pliers and push it through the firewall. It has two ears that click open once the housing is pushed into place.

[LooseyLucy71]

Originally Posted by Boog

You go inside and squeeze the cable housing with a pair of pliers and push it through the firewall. It has two ears that click open once the housing is pushed into place.

Thanks Boog! It was much easier to see and to remove once i smartened up and removed the gas pedal.

[Boog]

You are welcome.

[LooseyLucy71]

Good progress on Lucy this week! I got the radiator support, inner fenders, inside of outer fenders, and battery tray prepped and painted. I also cut and reworked the battery tray to go on the driver's side as lsnova71 did with his ls builds. My tray was shot, so I replaced it with a piece of 1/8" plate and welded it all back together. I also hung the radiator support, inner, and outer fenders. It's certainly nice to see it coming back together. On the interior, I replaced the fuel tank and filler neck grommet (grommet from classic heartbeat) and also installed sound deadening under the seat and on the back of the cab wall. I plan to do the floor pans and up the firewall as well, but there's some surface rust I'd like to address when the weather is warmer. For now, the carpet is back in. I'm leaving the seat and tracks out until the wiring is done to give myself a little extra room under the dash. It was quite the circus to get everything painted with it being 35 degrees out. I had the truck outside and plastic laid out outside. Had the heater going in the garage and the door opener in my pocket so I could have each piece and the paint preheated and only outside to spray. It worked out pretty well, I just had to open the door to vent off the VOCs a few times while everything dried. I wouldn't recommend it as a great practice, but for January in NH, it got the job done.

As for parts, I've ordered a 3.5 turn steering box from redhead, -6 AN fitting tools from summit, and a fuel pressure regulator and fuel pickup sock both from Amazon. All should be arriving early next week. My plan is to tackle steering and fuel first, then move onto wiring.

I'll also be fabricating brackets to mount the factory airbox from a Silverado on the passenger side. I'm aiming to use the existing mount holes on the radiator support and inner fender that the battery tray mounted to.

Also interesting to note, I measured my fender to ground distance before disassembly. As it sits now (no radiator, bumper, hood, cowl, and other little stuff) we are riding 2" higher in the front than with the 454 in there. With me sitting on the radiator support (175lb ish), it goes down 1/2". Might need to change the rear springs as I really like a little rake and really dislike negative rake.

[ironroad9c1]

Might want to put some dynomat on that tank ...keep the sloshing Quiet.

[LooseyLucy71]

Originally Posted by MrMeseeks

Im lovin the flat black in the engine bay. really going to look good with the ext color.
Also what is your wheel and tire size? they fit that truck very well.

Yeah I'm really pleased with how it's looking so far. It's making all that prep work worth it! Wheels are 17x8's and tires are 235 55 R17.

Originally Posted by ironroad9c1

Might want to put some dynomat on that tank ...keep the sloshing Quiet.

I was thinking of doing that. I'll probably leave that for the summer when I do the rest of the floor. I'm trying not to get distracted with too many side projects, but it made sense to get the dynamat in behind the tank while I had the seat out and was changing the tank. This summer I'll probably get back in there.

[LooseyLucy71]

Steady progress in the last few weeks. I received all the parts I had on order on my last update and began installing. I got my new 3.5 turn steering box from redhead and got it bolted up to the frame. I then started looking at how I wanted to configure the lines and pump. As I'm sure most of you know, the LSx uses metric O-ring fittings and the truck side uses inverted flare. I decided I wanted to run the stock lines, and just change out the HP side fitting to the one off my old pump from the big block. Since the LSx pump mount os much lower, there's very little room for the line to go anywhere. I decided to swap the LSx pump's casing out for the original. This worked fine, and I was even able to press the pulley back on once I found the threads on the inside of the shaft. They were quite rusty and had to be run with a tap. I then got a new stock HP line for piece of mind and discovered it doesn't really want to go to the HP outlet of the pump without inducing a lot of twist, since the pump is about a foot lower than stock. So I guess I'm left with 2 options: 1. get a 90 degree fitting for the HP outlet of the pump and see if that will work, or 2. Swap the pump casings again, buy adapters for the pump side, and try to use the lines that would go with the LS trucks. I'd like to keep the 71 BB housing and remote reservoir if possible, but I'd also like to get on to the next thing. Feel free to send your advice / opinions my way.

I also go going on installing my fuel system. It was my first time making AN fittings, but with the vise jaws, AN wrench, and Koul Tool I bought, it was a breeze and went together pretty quickly. I started at the sender, and decided I want to keep the original hard line from the sender to the underside of the cab. From there I go to AN line, pump, filter, then up to the fuel rail. the return line runs parallel to the supply and will go through a 90 degree bulkhead fitting up through the cab floor up to a weld on AN fitting to be welded to the sender once I drill out the boss. I'm planning to run the stock vent line as it was in decent shape and use the stock charcoal canister. I have all the AN lines underneath done and mounted, so I need to connect those up to the tank and do the wiring for the fuel pump. I have some pictures below. Does anybody know what the mount I ran over with the fuel lines is for?

I pulled the LSx harness out of the box again and went through and labeled what every connector was. This should make it easier to install. It also helps having one installed in the driveway to see the intended routing of everything!

I'm looking to get the fuel and power steering systems wrapped up, then move on to reinstalling the engine bay wiring harness after I fix some questionable wiring by the previous owner (wire nuts, really?)....

[Boog]

That bracket looks like the oe exhaust hanger.

[Grumpy old man]

^x2