Hello. On one of my 87s I have a set of accel runners. It is a stock l98 with headers exhaust and 2400 converter. I was thinking to take the runners and siamese them and port the plenum. Is this a good idea? If i remember you siamese them up top where they bolt to the plenum. I'd like to see some more rpm power with the car. Then i'll tune it. What do you guys think? Is it worth the effort? Cam and heads will be done later Thanks. Chris.

I'm confused. Was there a question here or were you just commenting to let people know what you were doing?

I was asking if it was worth doing. Im not doing the cam and heads for a while

Yeah, have at it.

I had a stock L98 with zz4 cam and exhaust. I picked up about 500 RPM with heavily ported SLP runners and ported plenum. Never dyno'd though, so I can't speak to the actual numbers. ...and it didn't feel faster really, but it definitely pulled higher, so that translates into performance.

....now add an aftermarket/ported base, and do heads and cam, and that's where that ported will really shine.

I'd like to hear your results too. I'm eventually changing my stock tpi with ported parts I have on hand but my long block is modified with ported heads and cammed, so my experience may be different.

I have a FULLY worked tpi (1.75" ports - 1206 base) and I shift it at 5500. (some times 56-5700) only been to the track one though with it. 3 runs with issues and such but the third run I knocked .3 off reving to 5500 ONE time (first gear).

i plan to go back in a few weeks after I fix some things. The higher I reved it the faster it went, both mph and e.t.

-(stock tpi ports are 1.48")

If it was staying stock id say no on the siamese think its overrated or a crutch for a base that hasnt had enough work
If you really want to make those hum, take a bandsaw cut them in half then go after them, wel together grind smooth and paint.
Siamesing wont hurt....but its a chitpot of work for ??gain. BTDT
Do not siamese your base

When you cut them in half u mean to make the cut vertical?