Anyone done this before? Of course someone has. I'm looking to start the project in about six months. I'm just curious as to what kind of ballpark HP figures I'll most likely see.

The project will start in six months.

 

It's been done. Very little of the factory TPI parts will remain when complete.

Too many variables to give HP figures. I know of a 406 TPI Vette that runs 10's, but you probably aren't going to spend the money that he's laid out over the years.

 

I'm looking for high12's/13's flat while retaining excellent streetability. The object would be to be able to run with LS1's.

 

theres one in super chevy with accel tpi making ~416HP

 

Not with those long-tube runners on there. They are "tuned" acoustically, by way of their length, to produce specific effects at specific RPMs, which don't change with engine displacement. In particular they are designed to reinforce cylinder fill at about 3600 RPM, at the expense of reducing cylinder fill at any RPM above 4500. As long as those tubes stay on there, you can't change that very much. The only thing that changes with engine size, is the RPM at which TPI's flow limit is reached. which of course goes lower with increasing engine size.

It chokes a 305; I doubt it will be much kinder to a 400.

I'd bet the guy that runs 10s with a 400 TPI probably has at least a 150 shot on it.

 

a mild 400 will get an f-body into the high 12s very easily, and inexpensively.

the two coolest (and least expensive) parts, though, aren't smog legal.

a set of vortec heads offers incredible bang for the buck. scroggins dickey has the vortecs modified for higher lift cams for less than 650.00 a set.

a stealth ram looks like a real hot and inexpensive setup, too. they started putting one on a camaro in the current gm high tech performance magazine and it looks promising. the author is a member here and is helping guys with it in the tpi section. if you do a search on "stealth ram" on the tpi board you'll find it.

if you're set on staying with the complete tpi, there's a member named mike crews whose 383 tpi is in the very low 12s with a very conservative setup. there's a thread in the tpi section on his car titled 383 vortec or something like that that is probably the longest thread on the board and is full of great information. reading it, the importance of careful, conservative parts selection and attention to detail become obvious. while he's admittedly not a great mechanic, mike is very thorough and does a lot of research before he makes any changes. he's about to run 11s on street tires with 3.23 gears and no power adder. i'm a tbi guy and still follow that thread because i've learned so much.

 

You'd lose the bet. It's actually a Miniram (quasi-TPI), and little things like carbon fiber front end, back-halved, etc.

 

Well if it's a MiniRam, then it's not TPI. Granted, it's fuel injection, but it's not "Tuned Port" injection. It's something completely else, that does not use acoustic tuning for cylinder fill reinforcement in selected RPM ranges.

Actually, if I were going to try to build a fast FI one of these cars, the MR is the system I believe I would use. It might be possible to get more power of an Accel ProRam, but that has underhood fitment issues in this chassis. The Stealth Ram looks good too, for small motors like 350s or even 383s; but its small runners (left over from the days when it was the "Street Tunnel Ram" with dual 450 4-barrels) put an upper limit on the HP that can be achieved that's considerably lower than what a good 400 can be easily set up to do.