Hello there, I am in the middle of planning my build. A little history, I've got a 1987 Pontiac Firebird Formula with the LB9 TPI motor and a 700R4, bone bone stock. I'm planning on building a L98, still deciding whether I want to stroke it to a 383 or just build a 350 and go from there. It will be NA. I don't want to LSx or LTx swap it, I want to keep the TPI intake, and I am desperately trying to find SLP intake runners. Any AFR or Edelbrock heads that I can run the stock intake manifold on? I know, I know, "why do you want to keep the stock intake", "LS SWAP BRO" and all that other stuff. I also know that somewhere out there is an intake manifold for TPI to Vortec heads. I adore the look of the stock TPI intake, and would love to continue to have it on my car. Any tips or other helpful information is appreciated. Thank you all.

 

The 87 intake has the 87-up non-Vortec bolt pattern. The pre-86 pattern is the same except for the angle of the two middle bolts on each head. Most people just oval out the holes with a high speed cutter or file, and go. Most aftermarket tpi base manifolds are slotted from the factory to fit either heads. Scoggin-Dickey still seems to have the Vortec TPI base available.

The wilder you go on the engine, the more you'll be choking it with TPI. 383 is a waste, imo since the tpi wont really feed it. Better heads are probably fine within reason, but you need to remember that the TPI has a tuned effect that is going to enhance or inhibit whatever engine it's paired with. After a certain point it's going to really choke the engine down.

 

On a L98 build, you could go with AFR 180 or AFR 195 heads. AFR 195 #1041 works good if you do some porting of the intake manifold and plenum and with SLP runners, you will get enough flow to support the heads. A 383 is doable but don't expect much more than 400hp if ported. The cam choice should be made by calling Comp cams or a cam company of your choice. Your intake will restrict you from making any more HP than around 400 max. If you can find one used, look for an Edelbrock TPI lower intake manifold. They are getting rare to find one any more, but they can be ported more than the stock manifold. Ask a lot of questions here, and with aftermarket companies for advice on your build. You will also need bigger injectors, 30lb, and a computer tune to get it dialed in. There aren't too many tuners that work with these old cars any more, but depending on where you live, TPIS in Chaska MN. does a excellent job of tuning. And just for your info, TPIS is an excellent engine builder also. https://www.tpis.com/parts/view/33 I have no affiliation with TPIS other than I use their Mini Ram intake and had Jim dyno tune my car. They are good people and very knowledgeable with these cars.

 

Aftermarket base and runners match well to afr 180 heads. 195's can also be used

 

I have a HEAVILY ported tpi on my RHS 180 headed 383. Its super fun. Stoplight to stoplight beast! ...but as i knew going in, and has been mentioned....ultimately itll hold me back. I shift at 4900 to 5000. ....but man its fun. No regrets here at all but its not for everyone.

 

I'm with Abubaca. I built a 357TPI with a real TPIS base and BTRs. I used Trickflow 175s to get back some compression as I used a bone stock rebuild of a 4 bolt 638 block to save some money. It only runs 13.2x @ a buck five but I've had DRs as wide as 295 on there and could liquefy them at will. I've got a set of skinnies for the front and have put the old boy on a weight loss program, (A/C gone, Stereo w/giant woofs in the trunk, gone, etc). As a matter of fact I'm debating throwing the rear seats overboard when I put the interior back together. Also, I've got my Holley Avenger all teed up for my winter project as I've been to multiple "experts" that can tune a 730 "with their eyes closed". Um, yeah. I actually think WOT is darned close but I got coughs, stumbles, surges all over the place and a wandering idle. If I could have a 12 second pass, I could die a happy man!