Ok so I've got a customer that is putting vortec heads on his throttle body motor. I've already gotten him the intake and so forth, but now he's talked to Holley performance and Holley told him that TBI is only good for 250HP, and I think that is complete bull****. I need some other opinions on it because honestly I haven't really messed with a TBI truck.

 

and yet you are sure a company that designs performance parts for this type of engine has no idea what they are talking about?

 

Title + material = contradiction. TBI isn't worth a ****, IMO.

 

THANK YOU!! MY WORDS EXACTLY!! Sorry for the caps..

Well you may be talking about Holley.. the only problem I have is the fact i've seen trucks that have TBI on vortec motors pushing plenty of HP.

Why would GM make an intake for a truck to put TBI on it if the TBI can't even hold up to the power?

 

the original TBI systems can support a fair bit more power with modification. Untouched that's all they're good for. The stock throttle body flows around 370 Cfm, which is pathetic. You can get ported ones that flow around 600 cfm. Next the stock cams are embarrassingly puny as and the heads are about as bad. The ecm in them is also very simple and requires returning for any semi serious change. Power can be made with them though, check out some third generation camaro forums, there's guys running 400-500 HP with early throttle body based systems.

 

I think you missed my sarcasm... the TBI is ****, holley is correct. The most I have EVER heard of a tbi making is around 400hp at the flywheel, and even that is a stretch. Show some dyno graphs of those tbi trucks. TBI makes a ton of torque off idle, which is why they may "feel" fast, but the intake design simply starves at higher rpm.

 

I should add that although they can be made to support power you'd have a far easier time going with a good carb or an aftermarket FI system if you don't want to mess with a carburetor

 

Well I feel you on the TBI because I think it's a **** design too. I love LS and I tried to sell him on just doing an LS swap in this truck but it was his father's truck and he wanted to leave it throttle body so that's the way it is. It's only going to push 300 MAYBE 325 MAXIMUM at the flywheel so I just want to know that this throttle body is going to be ok for that sort of power because to be honest with you , I don't really want to eat this $500 intake lol.. I just think Holley is ignorant for saying that even with the 670CFM throttle body they offer it is still only good for 235HP...

 

with a ported 454 tb with the ultimate mods done to it,it will run fine.Its the tuning thats going to be the task

 

Whatever you do don't put a Holley throttle body on it, I've had many bad reports regarding them. You're much better off with a ported stock or 454 throttle body. Do a search for cfm tech. If they still exist they offer ported throttle bodies and matched injector pairs. I forget who the go to guys are for burning chips, its been a while since I was into these engines