I have 350 Tpi. I wanted some recommendations on some mods to help with top end power.

 

Siamesed runners like slp's.

Or change tpi for stealth ram, miniram, single plane efi, pro flo xt, etc

 

Thing is the TPI system was designed for all its power to be made in the lower RPM range.

 

Agreed. Stealth Ram is the best bang for buck.

 

Don't want to change the TPI because I like the factory look. But would porting it help give more top end? And what about getting a bigger throttle body? would that help also?

 

Throttle body won't change anything. Porting the lower manifold will give better airflow but won't change rpm. Aftermarket runners will open up rpm but need porting make a real gain. The plenum needs to be ported to match the runners too. Factory runners are too thin to port. All that costs more money than a hsr and will give you less gains. That's why I suggested it. Don't get me wrong I'm replacing my factory parts with ported soon. The hsr is just a more effective design.

 

The length of a TPI runner along with manifold and head intake length determine what RPM the tuned wave effect will occur. If you shorten this length from stock unit, your power band will move up some. SLP's like Orr mentioned would do this since their runner length is shortened over stock runners. That alone would help out some. Mild porting on base would further help but maybe not to that great of an extent if you are not upgrading other items (cam, heads, etc).

 

Just put a full exhaust system. The best mod ever. And the biggest gains without a chip tune.

 

Yes

No, the runners are still the restriction. You will want a cam with much more duration over the stock one if your looking to rev higher, as the cam is after the runners, not before it like the throttle body. Port the lower intake, port the heads, and get a cam with the right amount of duration to suit your needs. Stick with the stock runners and throttle body, only drawback is a more aggressive idle, but most consider that a plus...

 

-Fixed