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[A-2 ace]

Whats up everybody!!! new to the forum, and wanted to get some inside on the guys who know best! I have a 1988 GMC Sierra 4x4 5.7 with true dual exhaust cat deleted with a 5 speed trans. I'm looking for some mods i can start out with to make my ride a little more fun to drive Thanks..

 

[Awest623]

*cough* ls swap *cough*

 

[Awest623]

Seriously tho, check out the ultimate tbi mods thread. If you have bigger tires maybe think about regearing. I haven't fiddled with a tbi but I'm sure some of the people here can help you

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[A-2 ace]

HAHAHAHA thats great.. I have a 75 k10 that i want to ls swap soo bad!!!! the 75 is parked right now gonna be putting a new floor pan, rockers, cab corners etc....

As for the 88 I was think about putting a chip in but haven't seen much on them.. I also want to put a 2in leveling kit on it and just all around make it better then oem...

 

[Schurkey]

Make sure that the truck has all of it's OEM horsepower, before you go looking to the aftermarket.

It's easy to erase power with incorrect ignition timing, fouled plugs, faulty plug wires or weak ignition coil. Low fuel pressure is a problem. Cam lobes worn round are a problem.

Start with a COMPREHENSIVE tune-up, including cranking compression test, and a check of the timing chain slack.






'Course, I'd begin by verifying the steering/suspension/brakes/cooling/transmission are in good condition before I got overly-concerned with hopping-up the engine.

 

[L29Sub]

This will work nicely. Solve those 'round lobes' issues.

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[Christian ojeda]

Whats up everybody!!! new to the forum, and wanted to get some inside on the guys who know best! I have a 1988 GMC Sierra 4x4 5.7 with true dual exhaust cat deleted with a 5 speed trans. I'm looking for some mods i can start out with to make my ride a little more fun to drive Thanks..

Your throttle body has to be the first to go, it's like a 2 bbl carb, you can push as much air in and out as you want but not enough fuel and you wont make any power, I'm not saying go carb but get a better injection system, if on a tight budget and you're okay with doing some of your own custom stuff go port fuel injection from a vette and get a fuel pump from a vette. Not positive but I'm pretty sure it pushes more fuel than our stock ones

 

[L29Sub]

If not emissions bound, I'd go with Q'jet. HEI distributor. Parts everywhere cheap. Easy repair if needed. Too simple. Something like the below pic. If you want port inj, you'll pretty much want a Camaro donor, or similar donor. They'll bolt to your transmission bell housing (up thru LT1 and LT4), as will any cast iron SB. As suggested, get a baseline compression, and oil pressure when hot. If both good, and no knocking at idle, hot or cold, use it. Those SB TBI engines are not going to be cheaply improved by much. LT1 and 4 are not ideal either due to odd motor mount positions and optispark, but are excellent power plants and readily available. All LS after LT. Older cast iron Camaro/impala 350s are cheap and have potential. Better heads, CR, intake, ad infinitum. Be careful going home-grown FI. Be better off with Fitech and good manifold. Headers. HEI and away you go. If your engine is good. Maybe small street cam while in there.
You'll need a donor vehicle for any transplanted GM port injection mods. OBD1 is what you want with factory port inj. Or no OBD (carb)....even better.

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[A-2 ace]

the motor is a 94 gm crate engine with 3k on it... i was thing of going carb but wasnt sure on what needed to be done besides changing out the dis. to a hei and slapping on a carb. and advancing the timing to 10 degrees instead of the factory 8 degrees... what headers would you recommend?

 

[L29Sub]

I'd go with a 4 barrel intake, HEI vacuum GM dist, Holley (600) or Q'jet (650) 4 barrel set for about 300 HP, and any short headers with 1 5/8" tubes. If manual, be careful with clutch linkage. Hydraulic clutch isn't an issue. The dist timing could start at 10-12*. Then run the engine and ramp it up gradually under a load until you hear detonation, then back off a couple degrees...for sure until detonation is gone. Keep in mind that an engine set up as I describe does not require an ECM. You can keep it in the system to short cycle the fuel pump. The carb only requires about 4 lbs of fuel pressure to function well. So the fuel pressure will require regulator or a different fuel pump in order to deliver 3-5 lbs of fuel pressure. The engine would be similar to late '60s in function. Good overall performance and easily modified without major additional carb, exhaust, intake changes. You can run regular or premium fuel, depending on the advance settings. All guages will function normally, but the AC will require circuit changes in order to function without a signal from the ECM. You will not need O2 sensors. A street cam such as a GM "Hot Cam" will add considerably to the overall feel. And still allow for reasonable towing. The 1 5/8 headers are high torque items, so if not towing, 1 3/4 could be used.
The big issue is your transmission if 4L60e. You'll either have to swap to a 700R4, or stand alone trans controller.
If manual, no problems with any engine mods. Your VSS feeds the dash so while the ECM copies the VSS signal, but the speedo and cruise work without an ECM. These changes are not cheap, but they are one time expenses that allow continued engine performance upgrades without remapping, additional tbi mods, fuel ratio issues, and maps that just ain't quite right. Both Holley and Q'jet can be easily jetted for whatever. The Q'jet is easier (IMHO) and cheaper to adjust calibration. Use popular dual plane intake, such as Holley Warrior or similar. The only downsides to this setup is it isn't emission legal, and carbs are cold natured until engine reaches operating temps in cold weather. Other than that, a good carb is far more dependable than GM tbi or fi. And this setup can be diagnosed and repaired without major expense, even in the back country. I ran that (30 year old) Q'jet in the above picture for 5 years without a sneeze. People forget how dependable those things are. A good addition to the above is installing an air/fuel ratio and electric fuel pressure meters for monitoring the jetting while setting up. Once done, its nice to watch your work.
The key is dont fall for "bigger is better". Stay with reasonable sized cam, carbs, intake, exhaust. A small block is a great street engine if done up right.

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