I have a few questions.

I'm about to buy a 91 firebird. I'm already bench-building a strong, streetable 350 for it. one of the problems I run in to is the heads. Will the lower plentim on the tuned port bolt up to any small block chevy head? My father-in-law owns a full machine shop, and seeing how I damn near qualify for welfare, I was just going to have him port me out a set of heads lying around. Are there any restrictions on the years, or types?

Headers. Should I go with full length, dual pipes, or shorties with a Y pipe? What about the emission tubes? Just looking for some advantages and disadvantages.

Last one. If I swap in a T-56, does it require a stand-alone computer? I read the article somewhere on this site but it didn't mention anything about the ECM.

Thanks guys
subject

 

Henry,

Welcome Aboard!

Or in your case, would that be "abroard"?

The TPI system changed slightly in 1987 to accomodate teh changes in all SBC heads in that year. the '87 and later heads have a slightly modified bolt pattern for the intakes. The center bolts on those heads is canted slightly outward to make access easier. You can often modify the intakes by simply elongating the center bolt holse to allow the fasteners to thread in at the correct angle, but tapered washers would have to be used to provide proper bearing under the head of the bolt. Simply for assembly, it would be easiest to use '87 and later heads. Aside from that, some of the earlier SBC heads have very poor intake port runner designs, making the choice even easier. Even though none fo the factory castings are "all that" as they come off the assembly line, the later castings have some potential with a little port work.

Your selection of headers is a function of th espace you have and the RPM at which you want the most power. Since you are planning to use the TPI setup, high RPM seems to be out of th equestion, so longer tubes would probably compliment your setup better.

As for the transmission, unless I'm mistaken, the '91 ECM diesn't do any transmission monitoring or control, so the selection of a T-56 shouldn't present any serious problems. Of course, there is always the question of the speedometer and VSS gear selection, and you'll have to have an ECM EPROM that is compatible with the transmission, but that is true of any swap.

Again, welcome to ThirdGen.org, and thanks for being there to represent us. We're all behind you.

 

If a lot of porting is done on the intake side, you'll be needing the same amount on the tpi base or need to look for an aftermarket base.

You don't need a new computer, but you should change to a t5 chip instead of running the automatic one(if it was automatic). As far as the VSS, you'll need to convert however many pulses per whatever(dont know, sorry) to what the firebird computer wants to see. You can use a box like this one http://www.dakotadigital.com/Detail....rtNumber=SGI-5 to fix that.

 

Yeah, give old bin Laden a sock on the nose for me, too

The good old 305 heads that end in casting numbers 081, 416 and 601 are very good candidates for a port, polish and intake valve enlargement. Cost will be around $400 US--and maybe even cheaper, since you're in tight with the local machine shop. That's the best bargain going that I know of, and I've looked!

Just follow the link at the end of my sig for a good overall description of the procedure, with pictures to boot

 

Yeah, just make sure that "sock" has an BGM-109 slid inside it first. HE or nuke - your choice...

 

Lets keep the nukes out of the middle east guys, I dont want to get tossed out of bed by a shock wave one of these days.