Howell Engine Developments Inc. has a Holley 4bbl TBI that can be be used on GM TBI engines.
Here is there website: http://www.howell-efi.com The 4bbl TBI is not on the website though. But you can order there "free" Fuel Injection Applications catalog that has the 4bbl TBI in it.
Heres a overview: Holley 700CFM 4BBL TBI with Idle Air Control & cable progressive throttle. The injector harness is modified for use with production GM TBI wiring. It requires a special Howell prom for the GM ECM. And its suitable for 383 to 400 SBC & all BBC engines. The part# is TB1249.
I'm going to E-mail them for more info on this, but this may be what I need to fuel the 383 that im building now. I was just about to give up on TBI & go with a carb, but maybe this is my answer. Do ya feel that a 700cfm 4bbl TBI unit would support 400+ horsepower? I'm wanting to get around 450hp +-15hp out of my 383 build up, think this will feed the engine enough air? Thanks, Bobby

 

It should.

Car Craft did a feature of the Commander 950 system with the 700 cfm TB and it came in at 390HP, 10 under the Super Ram IIRC.

https://www.thirdgen.org/techbb2/sho...=Commander+950

 

Interesting... Please let us know what kind of info you get back from Howell.

 

I did this several years ago. I talked to howell about how to put it together (just wire a 2- pairs of injectors each in series). They also provided a chip for me. It ran fine... not perfect since I didnt have any custom tuning but at least as good as a carbed car. Grumpy will chime in at some point and tell you that when he ran a pair of injectors on his test bench off a single injector driver they "sounded funny". I'm not sure how mine sounded but the car ran fine... although I did initially have a bad injector that took a while to chase down. I ran the 747 ECM at the time in my '88 t/a.

 

They E-mailed me back, they have stopped selling the 4bbl TBI. But do still have a few used units that were for testing that I've talked them into selling, at least me one. I'll let ya know how much I get it for. Dan W, I take it you are not using this setup now, why? Also what were you running before you installed the 4bbl TBI, a factory TBI? Tell me more about how it ran and was to keep running, any problems, gas milage and such. Thanks, Bobby

 

I was running a 350, ~ 9.5:1 cr, 70's style smog heads that I pocket ported myself, the cam was Lunatti hyd roller 219/227 112 LSA, edelbrock performer intake, etc. Ran fine, got about 11 mpg in town (stock was 16). Never put the effort into it to get it fully tuned since the project took a different driection... I've decided to go twin turbo and buy some nice heads so TBI just wont give the fuel I need. Took it to the track but had some issues with a serious drivetrain vibration that was causing the knock sensor to go off just before the 1/8 mile point. Based on that 1/8th mile MPH and altitude correction, I was making in the 330-350 hp range (at the crank). Not the best way to tell ya how much power I was making but its the best I can do. I'm not sure how much Howell is going to charge you for that TBI but it only costs about $20 to buy the connectors to modify one yourself.

I put this together back when I did the motor swap. Hope it helps.
http://www.fbody.com/members/workman/tech/techindex.htm

 

They told me $250 for one that they used for testing. They said that they had some injectors left for them too if I were to ever need any. How much is a new one? Was it hard to wire up? What about the IAC valve and TPS sensor? Thanks for the help, I'm going to look at the link you gave now.

 

$250 is a good deal.