Hey guys. I have obtained a tpi intake setup to convert my firebird from a 305 tbi to a 350 TPI. I was wondering about how you would go about porting and polishing the intake plenum and runners. Or if it would be worth the effort.
My plenum currently looks like this



Note that the holes for the runners are not perfectly round. Is there fix for this? Also, how would you go about smoothing out the inside? Forgive me if these questions sound a little dumb. I am new to Multi Port Injection systems.

 

I would gasket match it and then send it out to be extrude honed...

 

https://www.thirdgen.org/forums/post...545-post3.html
http://www.austinthirdgen.org/index.php?pid=21
http://www.eecis.udel.edu/~davis/z28/buildup/plenum/
https://www.thirdgen.org/siameseport

Polishing as such is a waste of time as you are not dealing with suspended fuel like on a carb motor.
Just smooth everything out

 

I definitely say it's worth it. I got the AS&M large tube runners, matched them to the plenum and base, 52mm TB and matched it to the throttle body, had the Super Ram manifold ported and smoothed about 2" in. Along with the accompanying fuel/chip/exhaust (see my sig) mods, my car made around 330hp/499tq at the flywheel. Not too shabby considering the Dart 165 heads I run.

 

I siamese ported the manifold on mine gasket matched the plenum and radiused the inlets to the stock runners. Stock, ported heads and it runs 12s. I'd say get out the die grinder.

 

Thanks for all the suggestions guys. As soon as the funds allow I'll be getting started on this stuff. Keep 'em coming!