PI HEAD QUESTION FOR ALL YEARS!

. Depending on who does the porting and comparisons they are within a couple cfm of each other throught the range. If you know anything about heads the midrange lift is where you want and need the flow because the valves spend the majority of their time in that range. When most people are talking about which one outflows the other I cannot understand why there is a big arguement over 5 CFM or under.
 
TopDeadCenter said:
Wheres KBOY when you need him.. :(

How many horses would i be robbing from myself if i dont do the PI Headswap..if i just go with the PI Intake and Cams...what would this give me..the reason im asking is changing to PI heads in a 96-98 motor will really bump your compression right? Well what do you do if your looking to eventually charge or spray? I am really thinking of staying with my heads..cause they're really not that bad..going with the PI Intake and probably Comp Cams..worth it?

What's up! Anyway not tying to flame anyone, but in my opinion the added compression is what I did not want. Yes spray works great with the compression, but I do not plan on doing that. Compression is great for doing N/A mods. And it is also true a .550 lift will out perform a .500 lift cam. The thing I am doing is for a blower application. The cams that I am using are great for blowers with the less lift. I want to try something different by using the PI intake on a NPI head with a blower. That is why I ended up getting the adapters. You can get the swirl grinded off the PI head but I did not want to go through the trouble of it. I am trying to stay as much bolt on as possible. You will lose roughly 10-15 or so rwhp without using the PI heads. Also to me it is not worth running premium for a couple of rwhp when I don't even take my car to the strip. All it should matter is what you want to do to your car.
 
mogs01gt said:
Put a .500 & a .550 lift cam in both heads

see which one of the two will perform better stock for stock. Its a waste of money putting cams into the Non PI heads when you have the option of the PI heads. 5-10 rwhp on a cam swap is worthless.
Check out the latest issue of MM&FF. The Comp cams added around 40 HP above 3100 RPMs (edit for misinfo). From 2000-3100 they were even with the stock cams and under 2000 the stock out performed the Comps. So my run with Kevin verifies that I have him from a dig but after 3100 RPM's he walks. I'm quoting the numbers from memory but they are pretty close. If I'm mistaken someone correct me.
 
kboy262 said:
I do think the test was on a PI head thou.
They tested 7 different grinds...(EDIT for wrong info). That is the one (the cam grind you have) I was refering to. The other grinds had better gains on PI heads across the band although a few lost power down low...nothing that 4.10 wouldn't take care of.
 
coramprat said:
Check out the latest issue of MM&FF. The Comp cams added around 40 HP above 3100 RPMs w/NPI heads. From 2000-3100 they were even with the stock cams and under 2000 the stock out performed the Comps. So my run with Kevin verifies that I have him from a dig but after 3100 RPM's he walks. I'm quoting the numbers from memory but they are pretty close. If I'm mistaken someone correct me.

They were CNC ported heads from TEA.
 
coramprat said:
They tested 7 different grinds...one was on NPI heads. That is the one (the cam grind you have) I was refering to. The other grinds had better gains on PI heads across the band although a few lost power down low...nothing that 4.10 wouldn't take care of.
No all of the tests were with ported PI heads they did use some of comps nonPI grinds.