91 zeee

since I am finishing up my 383 TPI, I'm now curious..... what is the fastest naturally aspirated f-body tpi car you've seen or read about? no stealth ram, etc.... just tpi?

FalconZ28

It sounds like you're asking what is the fastest TPI without bolt ons. There are heavily modified TPI plenums and runners/ intake that make much more power than stock - but even that involves siamesing the runners or switching them to higher flowing ones altogether. When you get to that point, why not just let different intakes into the game to play? It's all technically tuned "port" injection. I think I've seen guys on this forum around 350 rwhp, max before they ditched the stock intake and started walking up the power ladder again.

I will tell you from my research that if you're keeping the stock intake, runners, etc your power with a 383 is going to be choked. That many cubes breathes a LOT, and the factory intake would have a hard time keeping up. I'm assuming if you spent the dime on a 383 that you've already ditched the factory exhaust manifolds - after that the next weakest link is the intake IMO.

Orr89RocZ

iTrader: (20)

Tpi wise i have seen 11's posted here in fbodies. Some 10's in vettes

91 zeee

I bought Arizona speed and marine runners, edelbrock base and then ported the plenum and base. It looks like a huge difference; I just stared getting curious on what the fastest factory style TPI was; wondering if I might get close. Based on what Orr said; No, I won't be close. Didn't think I would be, but I wasn't sure if a stock style TPI had ever gotten out of the 12's.

Abubaca

iTrader: (3)

On these forums, TPI means long tube runner setups like stock. I agree that it's all technically TPI, but for discussion purposes, we're talking long tube runners. ...and ultimately you CAN of course make better performance choices, but a lot of people, myself included, like to pop the hood and have a stock style, pretty close to stock appearing engine, BUT...upgrade the performance. ...and while a carbed 383 may ultimately make more power, an aftermarket TPI on a properly head and cammed 383 will be an absolute street beast! ....even if ultimately, as stated....the TPI restrict upper RPM flow. ...I'm actually building one now!

Orr89RocZ

iTrader: (20)

What holds tpi back is the cross section of runners and bases available. Runners are too small in diameter and base head port opening is to small.

You wanna go fast you need rpm. Long runner can tune for high rpm but the area needs to be large to flow. Like short straw vs long straw. Try sucking thru them of same diameter. The shorter one has less resistance to flow and easier to pass flow. Longer ones need to be larger diameter

Base port needs to be atleast 1205 gasket size at the opening then taper larger to the runner connection. Seems like aftermarket bases can get close to that. For really hot setups using 1206 gasket head ports, you have to weld up the tpi bases to allow porting to that size. Thats more difficult and expensive