Ok guys I have a 350 with stock tbi injection and plan un upgrading it to handle my 400-425 383 bottem end. I want to know if one anyone else is doing this. What intake should I use...hood clearence is going to be an issue in my car. Should I go with the holley 670 cfm throttle body or should I go with the 454 throttle body with 350 injectors. Any body have a recommendation for someone to burn a chip for me at a really good price. There are people on ebay doing this but??? I need lots of input from you guys. Thanks a ton

 

there is a big debate on whether or not a Holley 670 or 454 TBI will be able to suppose that kind of power. If you did use one of these tbis you are going to need alot more than 350 injectors to feed it. I would just use the 80 or 90# injectors that come in the 454 TBIs. You can use just about any intake, you just have to use a carb to tbi adaptor if you go that route.

 

do yourself a favor and dont buy a chip off of e-bay.......i think there a rip-off and its kinda risky cause you dont actually know what they put in those chips....just my .02

 

Best custom chip (short of burning your own ) is from Ed Wright at fastchip.com IMO.
-Rich-

 

And even those are a rip off which brings you back to either DIY or know somebody that'll walk you through it or else go with a carb and mechanical dizzy.

 

I'm doing a 383 swap myself. I will be using the holley 670, but only for financial reasons. A 900cfm tbi will eventually feed her. 670cfm at 3" equals roughly 550cfm at 1.5"hg, which is what 4bbls are rated at. Generally, a 425 hp 383 will require a 750 carb, so I am doubting the 550cfm at 1.5" will support 400+hp. I am going to get mine dyno tested before the injection swap though, just to compare the differences.

 

ANy more input or budget option other than carburation...Thanks for the input so far

 

Does anyone know the factory HP for a 1990 SS454 truck or a 88-95 C3500 454?

 

I found a link, but its not that great.. 230HP/385 Torque , but its only showing 1987, not sure if it got better in the 90's.

http://members.aol.com/csmith669/enginespecs.html

Peace