So I have a 1988 V10 Suburban that started life as a TBI 350, TH700R4/NP208, with 3.73 gears. When I got it, it had a reman engine in it. I came across a good deal on a disassembled 350 short block out of a 1990 IROC a few years ago. I pieced it all back together. It consisted of the following:
1989 350 Roller block
Speed Pro forged flat tops
stock rods
GMPP LT4 Hot Cam
stock GM roller lifters
TBI heads from a 1993 K1500 that had been ported, and had new a valve train
The rest was all stock GM. The exhaust consists of Headmen (I believe) cheapo headers, and 2.5" dual exhaust, no cats, used Flowmaster mufflers. I eliminated the smog pump at this time.
I ran it that way for a couple of years. It ran okay, but the cam was too big, and the heads didn't flow enough.
During that time I blew up the TH700R4 and swapped in a SM465/NP208. It actually ran better that way, even with the PROM programmed for a stock configuration with an automatic.
Then I blew up the rear axle and swapped in a 14bff/Dana 44 combo from a 1975 K20.
This past fall I pulled apart the engine and upgraded it with the following:
Stock GM LT1 camshaft from a 1995 Z28
1.5 ratio Roller Rockers
Vortec heads (the lesser casting)
GMPP Vortec TBI intake
The rest was still the same (besides a new set of the same headers off of Craigslist) except I eliminated the EGR (no exhaust crossover in the Vortec heads, didn't feel like cobbling it together from the headers)
It runs okay, but not great. We hooked a Tech 1 scanner up to it. The block learn was close, it ran rich at idle/low RPMs, and lean up top. It also runs much better at higher RPMs.
The injectors are factory yet. I though about upgrading them before I have a chip burned for it. Should I go back to stock? Is there a decent aftermarket selection? Suggestions? Remember, this has all been done on the cheap.
Martin
1989 350 Roller block
Speed Pro forged flat tops
stock rods
GMPP LT4 Hot Cam
stock GM roller lifters
TBI heads from a 1993 K1500 that had been ported, and had new a valve train
The rest was all stock GM. The exhaust consists of Headmen (I believe) cheapo headers, and 2.5" dual exhaust, no cats, used Flowmaster mufflers. I eliminated the smog pump at this time.
I ran it that way for a couple of years. It ran okay, but the cam was too big, and the heads didn't flow enough.
During that time I blew up the TH700R4 and swapped in a SM465/NP208. It actually ran better that way, even with the PROM programmed for a stock configuration with an automatic.
Then I blew up the rear axle and swapped in a 14bff/Dana 44 combo from a 1975 K20.
This past fall I pulled apart the engine and upgraded it with the following:
Stock GM LT1 camshaft from a 1995 Z28
1.5 ratio Roller Rockers
Vortec heads (the lesser casting)
GMPP Vortec TBI intake
The rest was still the same (besides a new set of the same headers off of Craigslist) except I eliminated the EGR (no exhaust crossover in the Vortec heads, didn't feel like cobbling it together from the headers)
It runs okay, but not great. We hooked a Tech 1 scanner up to it. The block learn was close, it ran rich at idle/low RPMs, and lean up top. It also runs much better at higher RPMs.
The injectors are factory yet. I though about upgrading them before I have a chip burned for it. Should I go back to stock? Is there a decent aftermarket selection? Suggestions? Remember, this has all been done on the cheap.
Martin
The later version 454 Throttle Body uses a 30 PSI spring, so that's why I used the 5.7 liter Throttle Body injector pod. Anyway my point is a TBI upgrade with more CFM / Fuel will help the performance of your engine.
The real advantage of DataMaster TTS is once several performance changes have been done to an engine, the histogram shows were the fuel mixture is lean / rich. 
