Port the stock parts or get new high performance parts?

[Edmond]

I'm seriously thinking about rebuilding the motor this winter and I have a few questions about the intake parts:

Should I port the plenum or buy a high performance one?

Should I port the runners or buy some big tube runners?

Would porting the stock intake manifold suffice?

What am I trying to do? I'm not trying to make a monster, just something with a little more seat in the pants.

Depending on money, I may get the heads ported and get a slightly more aggressive cam.

I'm already considering the change to roller rockers. They aren't that expensive and don't seem difficult to install.

 

[FourAndAHalf]

i guess it would depend on your budget, if your pocket can handle it why not get high performance parts?

 

[vader86]

If keeping the stock-looking TPI setup, id do this:

Port the plenum, add some larger runners like AS&M and port match those to the plenum and siamese them at the base, then add a TPiS BigMouth or Accel base and port-match that to the heads and runners. Then change the cam to something like a Accel/LPE 211 or a TPiS ZZ9, and upgrade the valvetrain for it.

Definitely add the 1.6RR.

I believe that on later L98s, the manifold is the main restriction. Even ported it cannot flow enough to match the aftermarket bases. If push comes to shove, I would buy that before the larger runners.

 

[Edmond]

I believe that on later L98s, the manifold is the main restriction. Even ported it cannot flow enough to match the aftermarket bases. If push comes to shove, I would buy that before the larger runners.

That's exactly what I was talking about. I read in the TPIS catalog that even a fully ported intake flows significantly less than their Big Mouth manifold. I didn't really know how to interpret that because they're selling the Big Mouth's and I'm sure they'd like to sell as many as they can.