87 TBI 350 into my '76

[werewolfx13]

The '87 v20 I drove for a few months a couple years ago is getting parted out due to a severely cracked th400 transmission housing, and we haven't found a suitable replacement. For $450 I'm getting the TBI 350, the truck's entire wiring harness and ECM, the alternator, PS pump, smog pump, non a/c controls and heater components, both sets of rear springs (one was new when i was driving the truck, the other was a few months older), fuel tank, flatbed (and the steel to rebuild the headache rack), west coast mirrors (that I installed), interior door panels (my '76's panels are mismatched 1980 panels and are SHOT), and any other lightweight parts I want to take the time to yank.

All of the above is going into my '76. The engine had been rebuilt a few years prior to our purchase, but has less than 5000 miles on it. The truck belonged to a pig farmer who was in the process of rebuilding it a piece at a time, until his wife made him sell it after replacing the rear springs.

The 87 is going to be a 1 day gut, cut, and scrap. I've already got most of the harness out of the truck (the entire interior harness is intact and in my tool box). No problem there, the engine can come out a few days ahead of time so it will probably come out on monday unless we feel motivated to do it ALL that day.

Snags are:

1.Vacuum lines have almost all been yanked off and the underhood sheet has been painted over. Anyone have a diagram for TBI vacuum lines they could send me?

2.Half the plug wires have been pulled off both the plugs and distributor. Same firing order as a carbed 350?

3:Harness is for a non AC truck, my 76 has a 1980 AC cab on it, with everything disconnected. Can I just use the components for the non AC cab and make my own way of blocking off the evaporator opening in the firewall?

4:Rear springs, my 76 k20 has 53" springs, the '87 v20 donor has 56" springs. Is the difference in the rear hanger placement only, or both front and rear? My driver's rear spring has one broken leaf, a cracked main leaf, and another cracked leaf in the pack. Would I be better off finding a half ton 53" spring and building two 3/4 ton packs out of the '87's packs?

5:With a TBI sending unit and fuel pump for my '76's tank, and the 87 tank, sender, and pump on the other side, I'm assuming I can buy the selector valve at a parts store, and I think I remember seeing a link on here somewhere showing how the dual tank systems are wired, but I dont remember if they covered a TBI selector system. Any insight on this? The truck will be getting a flatbed, and I'm going to snag the tank brackets off the 87, so I won't have to worry about the filler neck really.

6:Are the 87 PS pump and lines compatible with my '76 steering box?

Thanks in advance.

[Jason S]

On the 1980 cab, you should be able to pull all the A/C out with the A/C wiring harness.  It's pretty much it's own harness. When I converted my heater only truck to factory A/C, i had to cut one hole in the firewall and cover part of another. For your conversion, if I remember correctly, you'll also have to cut one hole and cover the A/C plenum hole.

[werewolfx13]

Thanks for the info. Working on getting the engine out today, I had to come home to get my sawzall to remove the exhaust, but thus far I think I have everything else disconnected. Transmission was already out of that truck before I started, so that has made life much easier.

[bd]

1.Vacuum lines have almost all been yanked off and the underhood sheet has been painted over. Anyone have a diagram for TBI vacuum lines they could send me?

See figure.

2.Half the plug wires have been pulled off both the plugs and distributor. Same firing order as a carbed 350?

18436572 - Same as all Gen I small block Chevys.

6:Are the 87 PS pump and lines compatible with my '76 steering box?

'87 used a metric tube & o-ring configuration; '76 used an SAE flare configuration.  To keep it simple, use the SAE pump with the '76 steering gear, or the '87 gearbox with the metric pump.

[werewolfx13]

awesome, thanks. The PS pump on the 87 looks like it leaks anyway.

[werewolfx13]

Looking the '87 motor over a bit, it needs new intake manifold gaskets, and I think I'll replace the rear main and pan gasket while I have it on the stand. Thinking about a cam and lifter swap if I can do it on a budget, but I'm a bit concerned about having to replace the prom in the ecm. Something to give it a bit of a kick in the pants to get my '76 rolling. By the time the truck is done, it'll weigh in around 7500-8000 lbs (overbuilt front bumper, 8x10 flat bed, underbody tool boxes, partially boxed frame, dual 20g fuel tanks, headache rack and roof guard, and the truck will become the permanent home for my oxy-propane cutting rig [100 lb propane tank and "K" oxygen bottle]).

Whats the opinion on an "rv" cam swap in a TBI 350 with the factory prom?

[codyC10kid]

The 87-95 350 TBI i do believe came with 200hp 300Ft pounds torque (they where built for low end torque and gas mileedge),I'm doing the same build as you,Bored my 95 .030 over have 10.2:1 flat tops,port and polishing heads getting a Comp cam kit extreme 4x4 262 comes with cam lifters timing set springs lock retainers.All building with Electric fuel pump for under $2,000...Using my intake and carb that was on my old motor.Its going in my 77 K10.I'm probably gonna push 250hp and 350Ft pounds torque....But that's if you swap TBI for carb....The RV cam iv always been told that you don't need to swap springs and its the "biggest" cam with out hurting your motor....Me i don't want my springs to max out all the time,That's why I'm buying a cam kit...$350 for it,More low end torque to match the heads and You have a heavy truck and your gonna want as much torque as you can squeeze out on a budget.But I'm just throwing my opinion at ya.Good luck on what ever you decide

[werewolfx13]

Thanks for the input, I'm keeping the TBI, and looking to spend less than $300 total. I may just put the money into the ignition and some gaskets for longevity and worry about internals later.

[codyC10kid]

sounds good...as long as there isnt any knocking internals

[werewolfx13]

Engine went down for a full rebuild about 8 years ago by the original owner, and all the owners that have had it after that haven't driven it much. Has some minor oil leaks and needs a REALLY GOOD cleaning. Oil + mud + pig feces doesn't make for a good looking  (or smelling!) engine.