I am still in the process of building a 383 for my 92RS. I am trying to find out which TBI set up I should mate with the 383. Should I go with a 454 TBI or the Holley 670TBI unit?

 

Arent the both the same, or really similar? Go with the cheapest. I've seen people use both.

------------------
West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

A Holley 670 is going on my 383. Matter of fact, when I go to twin turbo, I'll run two of 'em.

Steve

------------------
Steve's Trans Am Temple

 

i would go for the 454 tb and just mod it to flow a little better, like the ultimate tbi stuff.just make sure you have enough injector to keep the new combo from leaning out.
good flow and a low price.

lata
tim


------------------
91 Camaro RS-LO3,Auto.
14.301 @ 94.39mph
The car is going street strip for next season. 13's here i come!!!!!
Edlebrock TES Headers, Cat Eliminator Pipe, Borla Adjustable Cat Back,Marche Pulleys, HyperTech Chip,Transgo Shift Kit,B&M Convertor(2000stall),Steve Spohn Rear Rig( all rod ends), Poly Front Bushings,Ported TB, 350 Injectors, Edlebrock Performer TBI Intake, Performer Heads, 1.6 Roller Tipped Rockers
http://www.mycar.net/mafb/registry/detail.cfm?id=299

 

they flow the same

if you could make the choice definately go with the 454 unit but if not use the holley unit but mount your stock injector pod on there

 

Steve,
If I were you, I'd run GM units instead of the Holley units if you plan on going with some sort forced induction (I'm caught in this problem myself with my holley 4bbl TBI)

The problem is the injectors holley uses have issues at higher pressures. Most forced induction systems use a pressure regulator that increases FP with boost to keep the injectors flowing the same ammount of fuel. IE: if you are running 15 psi fuel pressure and 10 pounds of boost, your injectors are actually flowing like they are at 5 psi. So with 10 pounds of boost, you would need 25 psi fuel pressure to keep the the same ammount of fuel. This is outside the capabilities of the holley injectors but not the GM injectors. Also consider that you may not need the flow of a pair of holleys of 454 tbi's. Thats almost 1400 cfm and way more airflow than needed. A pair of these also flow enough fuel to support 800 hp. A less expensive and probably better matched alternative would be to run a pair of GM 305 f-body units with well matched injectors for your projected power level. I like the idea of a dual TB setup especially on an older car... if done right it could provide a great look. You might also consider a multi point conversion. This is the route I plan to take.

 

Hey thanks Dan! I'm still considering all of this. I've heard about that pressure deal and will deal with it when I have to (the turbos are about six months away.) I may do like you suggest and just use the Holley body with GM 454 injectors - I'll ask the guys who are going to do this for me. You ever hear of RMCR? Stands for Rocky Mountain Competition something or other. They deal explicitly in exotic things like turbos and superchargers, DFI, etc. They have a twin-turbo'd 84 TA and are working on supercharging a Viper! Holy Monkey! My car goes into the shop on Friday to get the engine and tranny put in, along with a bunch of "specialized" stuff that I've asked for as well. Lions, tigers, bears... oh my...

Steve

------------------
Steve's Trans Am Temple

 

Heard of them yes... still havent been to their shop though. They are on that road behind the Wendys on Powers right?

 

I'm not sure where they are I've just talked to them on the phone. Trying not to get ahead of myself! First get the engine in, THEN get the turbos in...

Steve

 

Have you considered running a TPI unit with the 383?? Just curious cause I would like to build a 383 and I want to use a TPI unit!! I wanna try and make the engine look like a GM stock 350 (wont sound like a stock 350 though), basically I want it to be a sleeper. People look under the hood and say "ahh, my 5.0L Stang will blow your GM 350 away". Meanwhile I have 400+ hp.


------------------
Godti
'89 Trans Am (Red)
305 TBI 5spd

 

give me a year, i should have mine built. ive got it designed, but. its a lot more money to have somethin like that built than i thought.

i know you are all laughin at me. you just wait......

 

I had considered it, but I already have the TBI's and I want to be different. Anyone ever see a twin TBI'd twin turbo'd Trans Am? There is no way that my car will be mistaken for a sleeper so I don't really mind. Desktop Dyno says 445HP at 5500 and 466#ft of torque at 4000rpm - total cost is close to $3500. Turbo's will be impossible to believe...

Steve



------------------
Steve's Trans Am Temple