3800 Intake Manifold Porting

[twiztid]

I am going to be installing my LP IC sometime in the next couple of days as the car gets put back together, and I was wondering what some of you have done to port the intake manifold. I am assuming that I would just need to take a die grinder and open up the inlet, but I wanted to double check before I did anything stupid.

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[sgtp]

The one rule to follow is do not gasket match the runners unless you have gasket matched heads. All that leaves you is widen the inlet on top, polish smooth the runners, and smooth out as much of the inside as you can from the top inlet. I put a knife edge on the ridge down the center. I guess you could remove the posts inside too.

I think people still tap and plug the water jacket holes going to the TB when they do ICs but I may be wrong.

 

[rob]

Dont know how much your really going to gain by porting the manifold alone. By a gasket match is suppost to yield 17%....

 

[Mike K]

Plug and tap eh? I just installed replacement O rings and decided to let the IC housing be the "plug". So far so good.

As for the intake, when I redo my heads I plan on gasket matching the intake as well as the heads. The important thing, as mentioned above, is not to gasket match the intake without also doing the heads as that will result in excessive turbulence. In addition to the ports you also want to lengthen the main inlet to the size of the intercooler core.

 

[rob]

If its still apart it may not be a bad idea to plug those coolent holes. Coolent is coorosive....The new red isnt as bad as the old green stuff....Mainly due to the increased use of o-rings in newer engines....

But if it leaks you'll probably wont know until its too late....If you dont notice the white smoke its hydro lock city....I may have a manifold tapped and plugged already for exchange and 2 cases of Lite(service fee) if you dont want to take a chance. PM if your interested...I'll be in the garage all day.

 

[nitrous]

If you do end up porting the intake runners for any reason, make sure you "slant" port them to keep velocity, straight porting will be more like to hurt performance than to help.