87 GMC engine swap

[nascarmikeb]

So I have an 87 w/ stock 305 TBI
I bought a nicley worked 350 4 bolt that has been nicely built up. Nice cam Edelbrock Performer intake edelbrock 650 carb and many other goodies.
My question is will any on the factory harness wires connect directly into a delco-remy dizzy or will I need to find another power source for the dizzy?

Mike

looking forward to my swap on Saturday

[Desert1957]

Should have a TBI off a 350(5.7) or change the injectors
Your distributor will work , just install it , plug it in

Biggest problem is ANY camshaft with a rough or uneven idle will cause MAJOR problems with your TBI setup. Personally I would change the camshaft before the engine goes in, Pick a TBI friendly cam

Buy a "Re-flashed" chip for you computer

I did this swap a few years back (305 to 350) everything will bolt up fine.

Desert

[INSIDIOUS '86]

His truck will be running the proper induction with a carb

So all he needs is power to the distributor
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[ed70]

Boo tbi, hooray carb

[Desert1957]

Originally Posted by INSIDIOUS '86

His truck will be running the proper induction with a carb

So all he needs is power to the distributor
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Yes, I thought by him referring to the original engine setup he was going to use the TBI.

Thread should have been (How to I install a carb engine in a TBI engine bay?)

Still need a heavier wire to the HEI (If that's what going in it) None of the factory TBI distributor wires are the correct gauge wire.

Desert

[rfmaster]

Desert

Do the right thing - TBI works much better than any carb in a DD.

1) You need a TBI friendly camshaft (there are plenty of them - just ask).
2) Find 64 lb-Hr injectors from a 5.7 L truck. Local pick your part JY has for $10 each. The 50 lb-Hr from 305 will go lean at stock fuel pressure.
3) If you get TBI friendly camshaft a stock 5.7L calibration ASDT, ASDU, ASDW, ASDX, ASDY, ASDZ EPROM will be a good start. A common 1227747 ECM was used with 305 and 350 alike. EPROM calibration is the only difference (on ECM side). A custom tune will deliver additional performance.

To my carb friends - it is time to look around.

//RF

[pontgta]

Originally Posted by rfmaster

Desert

Do the right thing - TBI works much better than any carb in a DD.

1) You need a TBI friendly camshaft (there are plenty of them - just ask).
2) Find 64 lb-Hr injectors from a 5.7 L truck. Local pick your part JY has for $10 each. The 50 lb-Hr from 305 will go lean at stock fuel pressure.
3) If you get TBI friendly camshaft a stock 5.7L calibration ASDT, ASDU, ASDW, ASDX, ASDY, ASDZ EPROM will be a good start. A common 1227747 ECM was used with 305 and 350 alike. EPROM calibration is the only difference (on ECM side). A custom tune will deliver additional performance.

To my carb friends - it is time to look around.

//RF

I went and looked at many trucks they did this to, and asked my self why? I guess i am a bigger fan of TBI. If i did end up with a non TBI, i would have to converted it.

Figure its just preference though..

[Jonboy]

Originally Posted by pontgta

I went and looked at many trucks they did this to, and asked my self why? I guess i am a bigger fan of TBI. If i did end up with a non TBI, i would have to converted it.

Figure its just preference though..

That's what I did, too.

[foamypirate]

Same here. Bought an 84 with a bad inline-6...would've been easier to throw a carb V8 in it, but I'd rather have the reliability of TBI. So that's what I'm doing.

[nascarmikeb]

I got a sweet deal on this very nice and 350 scat crank & rods, +.30 bore, line bored, ceramic headers, 2.02 heads, .501 lift comp cam w/ roller lifters, chrome everywhere. edelbrock 650 and performer intake, complete flowmaster dual exhaust and tail pipes. Total package.
This is my 1st performance engine. It is going in a very nice 87 swb gmc.
I will disconnect all factory wiring & carefully wrap it, because I am sure 1 day I will want to return to a TBI setup. I just want to stab the engine in as, and play around a little.
Gotta get a 3,000 stall converter, running a 700R4, w/ no shift kit. stock rear-end gears.
So this is gonna be a fun learning project.

SO I will figure out fuel, electrical connections to dizzy this weekend.

will take before and after pics & will post on Saturday

Mike

[nascarmikeb]

This is not my daily driver, just a project!
Any idea if once I disconnect all wires from engine, if electric fuel pump will still pump. I have bought an inline fuel pressure regulator to step down the pressure to the carb.

Also, I know I need a hot wire to feed the dizzy, any idea the best location to pick up a hot wire tied to my key switch that will send fire to the dizzy.

Mike

[redsled87]

Originally Posted by nascarmikeb

This is not my daily driver, just a project!
Any idea if once I disconnect all wires from engine, if electric fuel pump will still pump. I have bought an inline fuel pressure regulator to step down the pressure to the carb.

Also, I know I need a hot wire to feed the dizzy, any idea the best location to pick up a hot wire tied to my key switch that will send fire to the dizzy.

Mike

There are some places on the fuse panel marked IGN that you can put male spade terminals into. They are on the upper left of the fuse panel. That's how I have mine done. This is the way to go. TBI is ok for a DD but, for perfomance, carb is the way to go. I've been carbed since '99.

[spencer_41188]

the pink wire cut the pink wire lol

should be a pink wire that goes to the factry dizzy its the switched power for the dizzy or you can run a wire from the fuse block and theres holes lables ass., keyed ass. and so on

had a 350 with that tbi crap on it now i got a dual-quad fed 383 stroker i just pulled the computer cut the harness at the firewall and started pulling then again it was a fire truck "wireing nightmair" but now im thinking about getting fast ez efi but its a 4 barrel that flows 1000cfm insted of the factry 2 barrle that only flows 500cfm if that

[NorthwestGrudgeRacer]

What trans are you going to be running i didn't see that if you are running a 700r4 your going need or make a bracket or find on off like a 84 for the tv cable.

If you are going to just carb it find a HEI out of a 78 or so non compter car truck add power and your done. hope this helps

[nascarmikeb]

Originally Posted by NorthwestGrudgeRacer

What trans are you going to be running i didn't see that if you are running a 700r4 your going need or make a bracket or find on off like a 84 for the tv cable.

If you are going to just carb it find a HEI out of a 78 or so non compter car truck add power and your done. hope this helps

I am running a 700R4, will need to put a shift kit in it.

[nascarmikeb]

So today, I got the 305 TBI pulled. swapped over the PS pump and the altenator. Really had to figure out how to use the existing fuel lines w/ the electric fuel pump. Decided I am going to use the electric fuel pump, use an inline fuel pressure regulator. Gonna cap off the return line, since there is no return line from the carb. Found the pink wire in the harness, that I will use to fire the dizzy. So hopefully tomorrow, I will have it stabbed in and fired up!

[nascarmikeb]

So my brother and I finally got the 700R4 bolted up. We got all of the fuel lines configured and hooked up. I decided to use both existing steel fuel lines. My original plan was to use the in tank electric fuel pump, but I wasn't able to get it to pump. My guess is that with all of the wiring harness unused, the circuit to the fuel pumps in not complete. No problem, I hooked up the mechanical pump, and it is sucking plenty of fuel through the in tank pump.
Only other issue is my throttle cable bracket off the 305 TBI. I need to get a throttle cable bracket for a carburated engine.
Overall, it runs great!! Excited to have a whole bunch more power than the 305 TBI!
Any ideas on how to remove the main wiring harness out of the firewall?

[INSIDIOUS '86]

Just sniped all mine flush then unpinned them from the connector
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