Hello all. I have a few questions. I am in the process of gathering parts for my TPI swap. The parts are going on a pre-86 SBC (383). I have found a TPI setup for a decent price, but it is for an 89 305 complete with distributor, sensors, harness, & ECU. I know that I will either need to get a pre-86 base or modify the post 87 base. I am also aware that I will need to get bigger injectors.

My questions are

1. If I get a pre-86 base, will the 87 & up sensors, emissions, etc work with the older base? Or, do I need to get all new equipment to make it work?

2. Since the TPI setup is for a 305, do I need to get a different ECU or can this one be retuned to support more fuel, spark, etc? Can this be accomplished with a simple chip swap?

3. What size is the stock throttle body (air inlet)? I have seen larger 52mm & 58mm TB's. Do you all recommend a larger TB to support the engine, or would the stock unit suffice?

4. I have been reading around about knock sensors possibly having problems with gear drives. My engine has the quiet Pete Jackson gear drive (which I would like to keep). Would a LT4 knock sensor solve my problems or is there another route that I should go?

5. Lastly, do you all think it would be cheaper to just find a 350 TPI setup instead of modifying the 305 setup? The guy wants $175 for it, but I would at least need to get bigger injectors if nothing else.

The setup is going on a pre-86 383 with world heads, mild crower cam, full roller rockers, quiet gear drive and 9.5:1 compression. All of this is going in my 92 Chevy Silverado short cab, short box, 2wd. That being said, torque is my goal since the truck weighs 4k lbs without me in it. Also the truck needs to pass emissions and I would like it to get decent gas mileage. It is not a daily driver, but I would like to be reliable enough to be one if needed. That being said, I would like to keep most of the sensors on the system.

Thanks in advance for all the help. If yall can think of something that I over looked, please feel free. I greatly appreciate it.

Thanks.

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1. No problem with the base. Everything will fit.
2. PROM tuning. Check out the DIY PROM forum.
3. 48mm. Most people go with the bigger ones. Unless you upgrade the base, runners, and port the plenum, it won't make much difference. What's interesting is the GM crate 502 Ram Jet engine makes 502 HP with a 48mm TB. . .
4. A 350 knock sensor will probably work. If you get excessive counts and it's not "real", the gear drive will probably have to go. I can't cite reliable data either way.
5. Doesn't matter. In order to support a 383, you're going to have to change out everything that makes a 305 system different from a 350 system, anyway.

Most of what you overlooked is in #3 & #5 above.