Intake Runners - modification to stock runners?

[RoyalViking]

I have a '89 TPI. I had to remove the intake to replace the silicon in the intake valey and was cleaning the intake runners before I put them back on. I noticed there are casting patern bumps where the transition of the tube to flange occurs. I do not have the money at this time to replace them with aftermarket runners. Does anyone have information on cleaning up these areas. I still have not assembled the intake runners and plenum and can take advantage of the moment.

 

[PLRX]

I had a Z28 with the TPi engine and I had the same project. I cleaned the runners with simple green and a baby bottle "brush" cleaner. If the bumps bother you, you may sand them down with sand paper or a drummel.

 

[RoyalViking]

Thanks but I've already cleaned them so that I can install them.

I am asking if anyone has removed the casting patern match lines to improve performance rather than replacing the stock ones with high flow aftermarket runners.

 

[Edmond]

Thanks but I've already cleaned them so that I can install them.

I am asking if anyone has removed the casting patern match lines to improve performance rather than replacing the stock ones with high flow aftermarket runners.

Yes, a lot of guys do that. They also match the intake to the size of the runner ports as well.

The big restriction is the intake manifold. You could port that as well. Our L98 intakes were originally designed for the 305 engine when GM wanted to kill the 350 in favor of the 305. They decided to keep the 350 at the last moment but didn't design an intake manifold adequate for the 350 throughout the whole RPM band. Therefore, the stock TPI power hits a big snag at 4800 RPM's.