Hey guys. I'm planning on scooping up an Accel/Lingenfelter TPI base manifold for my 305.

I was wondering what kinds of gains I can expect paired with my existing SLP runners and port matched plenum. I know that new heads will help heaps also, but for now they're gonna be stock. What kind of gains can I expect with both stock heads and aftermarket heads when I toss on this manifold?

Don't know how you will gain but it will be a good choice and the best TPI manifold. It's better than TPIS Bigmouth and Edelbrock.

It's a very good manifold, but I doubt you could see more than a 10 hp gain if you run it with stock cam & heads.
You do have the opportunity to block off your EGR/heat crossover passages when installing the new intake. This can lower the intake temp and give a little power gain that way.

The restriction in the heads around the valve seats will negate most of your air-flow gains in the rest of the system.

Exhaust improvements always show big gains, and will accent your planned intake & head upgrades.

The car currently has edelbrock Ceramic coated headers with edelbrock Y-Pipe and flowmaster catback. I'm plan on redoing the exhaust system but keeping the headers. Also the car currently has SLP runners. All this was done by a PO. When the block that was in the car when I got it developed a rod knock, I port matched the plenum to the SLP and ground ALL of the restrictive blocks out of it.

Another question I had. I did NOT polish the inside of the runners. Would it be worthwhile to grab a dremel flexshaft and do this while I have them pulled off or would my intended use for the car (street) negate the benefits?

Also, this has me wanting to put a lingenfelter banner across the top of the windshield once installation is complete. Do you guys think I have the right to do this or will I get flamed?

If you can back it up, no one will flame you. Lingenfelter developed some of the best stuff for TPI cars, most of it's been unchanged for 20 years or better now. I'm running an accel/lingenfelter base/runner combo with a matched plenum and 52mm TB. Keep us posted

Where are you guys finding the lingenfelter tpi base, i looked on their site and didnt see anything there or anywhere else.

Maybe im just looking in the wrong places

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWNX%3AIT

They pop up from time to time.

They are not readily available anymore. You used to be able to have your stock stuff sent to them for porting to match, or nearly match their stuff. I believe the current Accel base is as close to the Lingenfelter one as you can get these days.

I have this base and paid big bucks for it 3 years ago (400$). It is not polished, and was brand new. I blocked off the EGR and made the appropriate changes in the chip.

I installed ported plenum, as&m big tube runner and this base along with a few other mods. All of this COMBINED made a big difference that is for sure. My bottom end is NOT stock either, but I did feel a difference with my setup.