Will 454 injectors fit in a 305 throttle body? The reason I ask is because a new 454 TB is a LOT of money. I know that the bore in a 454 TB is bigger, but I can have my 305 TB bored out at a machine shop and save about $350-400.

 

The 454 injectors will fit but would probably be a little to much for a stock lo3. 40 pounds to 90pounds is a big jump. Try 350 injectors or police injectors. As for boring out a 1 11/16" tbi to 2" can't be done. They don't leave enough metal to do so on the tps throttle return spring side.

 

Actually it's a 383. I've got 350 injectors in there now.

 

i am running 350 injectors@11.5psi in my car and i actually hafta lower the fuel pressure to make it work better even with all the air that my combo uses it is still too rich.

lata
tim

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I can see how you would have to lower the pressure having an LO3.

 

you guys cant just change injectors without prom work. Your car will run like $hit.

 

oh and the stock TBI unit can only be bored to 48 mm

the 454 uses 52 mm blades

Look for used TB's

I got mine for 50 dollars

 

ebay sells em for around 200 all the time. (the 454s and holleys)

pablo is correct, ive researched this personally. the small block tbi can only go to 48, and thats pushing it.
but at 48mm, and the ultimate tbi mods. you shouldnt NEED a bigger tbi till you are over about 340 horse power.

pablo is also right about chip changing. if you want to run such a large injector, you CANT just drop pressure to 8psi to compensate. its a more complex system than that. not much more complex . but just that wont do.

if i were you just stick with the 350's and boost pressure. till it runs right. ideally you would be doing chip changes, but not totally necassary.

 

chip changes ARE necessary.. unless you are content knowing that a carburetor could easily outperform you. IMHO if you arent doing the chips theres just no sense in staying FI

 

I got a chip from Street & Performance and the car runs great with the 350's but I believe that there is always room for improvement. I'm just looking at the possibilities. Before I do any more changing the fuel system, I'm getting a 3.42 rear. I'll learn how to burn my own chips in the future. The reason I didn't just go and buy all the necessary tools and software is because I needed the car running good quick. I'm sure it takes some time and trial and error to get proficient at burning chips that suit your desires. I do all the work on my car that I can do with confidence and since I never had messed with chips at all, I didn't want to get in over my head.

 

Point taken.

'If you are going to use, efi. and modify it, burn your own chips. otherwise get a carb.'

but still. need could be should. but if you dont change chips. you are just applying bandaids by adjusting the pressure etc.. and that is one thing you are trying to get away from by not using carb.