Gasket matching the Heads & IM

This is not an easy answer because everyone does it different and no-one has done back to back dyno testing that didn't involve a bunch of other changes.

PROPER gasket matching of the intake manifold can be worth up to 20-30cfm. WELL worth the effort. A poor gasket matching job is worth nothing.

Most gains come from a proper competition valve job.

Spend a little extra money there and also spend some time on the combustion chambers. It won't pick up flow as much as it will reduce detonation sensitivity.

I'm glad you are taking this step. The results will be well worth it.
 
I hope its a good job, I hate to say it but the guy almost died laughing when I told him what kind of car it was for. He normally does Big Block drag cars. He asked me why I was doing this to a SC and I told him that I wanted a sleeper that I could make some money with. he said that I'm on the list and he will get back with me about pricing. So I'm going to have "almost" the same mods that the MPX test car had......+ I'm gonna spray it
 
I can tell you that the car with some spray is sick. We put a stealthy 100hp shot on the MPx car and it made about 450rwhp and some sick amount of torque but I'm not sure how much because it kept spinning the tires on the dyno. It's pretty ballsy on the street, not many cars will hang with it. :D
 
I can tell you that the car with some spray is sick. We put a stealthy 100hp shot on the MPx car and it made about 450rwhp and some sick amount of torque but I'm not sure how much because it kept spinning the tires on the dyno. It's pretty ballsy on the street, not many cars will hang with it. :D

A car is only good as its tune........so what can you do for me?
 
Question when you gasket match the IM should you radius the inside to the mounting surface or leave them at a sharp corner as they enter the head, gut feeling would say radius them?
 
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It should be noted that Rich only posted what he did to his manifold, not what works best. I do not recommend cutting out the air diverter.
 
I've read it spoils the air flow. There are several good articles on the web about how porting gone wrong, especially over-aggressively will hurt performance vs. improving.
The air flow under pressure seems to be the biggest factor, maybe more important than volume.
Just my two cents, but I'm a newbie to the SC world.
 
I ported my own non sc 3.8 heads a few years back. Retaining the stock dismal 1.78/1.45 valves, my flow numbers were 214 Int and 143 exhaust.
 
Considering the ability for the intake flow to improve significantly with only porting, anyone ever experiment with only increasing the size of the exhaust valve to help bring the intake/exhaust ratio to .80?
 
Unfortunately, the size of the bore and chamber due not allow for more than an 1.9-2.0 Intake and a 1.6-1.65 Exhaust. Some have posted flow numbers of about 230 Intake and 180 Exhaust which is .80.
 
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