I have a zz430 motor currently fed with a holley 750 VS. I would like to go fuel injection but dont think I could swing the cost of Port injection. The car still has the computer in it for a 305 TBI.

1 Can I just find a larger TBI and use the same computer? I would like to buy a prominator to change the fuel and timing values of the computer while I drive.
2 What TBI do I need to use to feed 430 horses.
3 Will my intake stock fuel pump keep up?
4. The intake I have now is the GM version of the airgap for the fast burn heads, will this work OK?
5. What are the comparisons of TBI to carb. What will happen in terms of performance and mileage. I currently get 22 mpg on the freeway with the carb and a t56
6. What is the number of the ecm that I have now, 89 RS 305 TBI

Im sure I will have more questions as I go. I would just like to get better throttle response. I thought about going with a ramjet intake But I dont have the money to swap buy the intake and a different wiring harness right now
Thanks For your help guys

 

Okay, I'm going to get flamed hardcore for this I'm afraid, but this is the best answer I could give.

TBI is a fine system under two conditions:
1) It matches the motor combo
2) Its properly programmed

The second part is somewhat minimal I suppose, since someone using like a 670 Holley TBI could get a laptop and dig in, and someone buying a 900 cfm custom 4-barrel TBI setup will likely either also program it themselves, or pay someone else to. Either way, the calibration is taken care of.

Here's the catch though, to the best of my knowledge, a 670 cfm holley TBI (which many have tried) will only support around 4500-4600 rpm max. This is simply a matter of (rpm X displacement/3460) (I think thats the equation) which gives you the CFM you need to flow a certain rpm. I tried using a 670 on my 350 and guess what? My dyno sheet stopped climbing at 4500ish rpm, even though my cam and setup builds power past 5500 easily. (Basically, a TBI system is flowed at higher pressure than a 4-bbl carb, thus, 670 cfm of 2-barrel TBI, is around 490-470cfm of 4-bbl carb).

The bottom line? Either pony up and buy a 4-barrel TBI system or dont bother. I'd say keep saving and go for the ram-jet, which is a very nice system. Whatever you do, don't do a tuned-port swap or something like that. Tuned port builds torque, not power - at least in stock format. I wouldn't use ANY stock system or similar derrivative on a 430hp motor.

Ty

Before anyone takes offense *should they* please consider that what I say is a combination of dyno-work and research done by my local performance shop. I'm not just paraphrasing Car Craft or something...