Port and Polish

[Grandmarchris]

Can you even use the PI inkate on the NPI heads???

[zwack88]

Yep. You use non pi gaskets. There is a write up over on CVN.

[turbo2256b]

We can port the non PI heads to match the PI intake. Ported non PI heads will out flow ported PI heads. The expence of PI or other aftermarket cams are not realy worth the cost on ported heads. Increasing the vale size works better. We also have our own valve design designed by us which flow better than the aftermarket ones. They are also a specal size flownd to flow better in the combustion chamber.

[Grandmarchris]

I would go to PI's but im worried about...

Mainly making the trottle cable work like it should when I move the intake forward and to the right...EGR shit vacum line etc

And its a 92' REP block I don't think PI heads will fit it

[drock96marquis]

While the heads are off have the valve seats ground down so you can run PI cams in the nPI heads.


Modular head porting is no simple matter, don't cheap out.


You can use a PI intake on the nPI heads. Use PI gaskets, with a dab of RTV in the small corner of the front water jacket.

This makes for 2 dabs of RTV - vs 8 beads of RTV (1 on each airport) trying to use nPI gaskets for the PI intake swap.


Might as well go all-out and convert the car to OBDII as well.
It would prove more cost-effective to just find a donor 01-02 CV/GM and nab the wiring, engine, PCM, etc.

[Chevro]

what about port/polish heads, and port matching stock heads/intake and exhaust on a 92?

[turbo2256b]

All the Mod heads run about the same to port 600.00. Some have more material to remove than others. With options they can run up to around 1000.00. The 4 valves start around 1000.00 and go up with options.


I sugest port matching Non PI heads to the PI intake or there is a severe port mismatch. The PI intake is tuned to aroud 1000 RPM higer peak.

[Grandmarchris]

So it would be cheaper to do the simple head swap

[turbo2256b]

So it would be cheaper to do the simple head swap

Depends on the HP you want. HP costs money.

[Grandmarchris]

Im debating between 4 options

Running a PI intake with ported NPI heads

Running PI everything

Running with an edelbrock PI intake only

Converting it to carb and running a barry grant speed demon or holley 575 cfm carb

[turbo2256b]

Im debating between 4 options

Running a PI intake with ported NPI heads

Running PI everything

Running with an edelbrock PI intake only

Converting it to carb and running a barry grant speed demon or holley 575 cfm carb

Havent seen a 4 bbl intake for a mod motor I think there are some now. The BG carb in all the test I HAVE SEEN out performs the Holly enough to warent the cosst differance. I suggest vacuum secondary with out heavy cars. Head porting would also be easyer to tune for. Porting can be good for 100 to 150 HP but is expensive to accomidate with FI.

[p71towny]

Carb conversions for these cars are retarded money. You could bolt on a supercharger and be done with it for that money.