go with the ITR pistons, JDM ITR pistons as has been mentioned numerous times in the thread already. They have deeper valve pockets than the P30's, which allow the use of larger cams and are less likely to have P2V contact issues. They have a slightly higher compression height than the P30's meaning they have a slightly flatter top on them than the P30 promoting flow and a good burn in the cylinder. They also have a lubricant on the skirts to help reduce friction. All these things are advantages.

 

There should not be ANY contact issues with the P30's since they are the same height as the stock LS pistons.

And compression wise, all of the "internet" calculators I type into (not saying they're accurate though) the P30's should be 11.6:1 - 11.9:1, which is much higher than the ITR's.

 

Try running those stock LS pistons with big VTEC cams and see if you have any P2V issues, especially if you have any decking or milling or crazy cam timing settings. The problem won't be the height of the piston, it will be the size of the valve reliefs, or lack there of, causing the P2V contact.

That's the problem with internet calculators, they only give you ball park ideas about compression and often miss out on the accuracy of different compression heights between pistons. Use whatever you want but if you're smart and truly want to make the best choice for yourself, take the time to research what I have said. There's no "bad" choice here between the two pistons we're talking about, just a slightly "better" choice if you will.

 

i have pout p30 and pr3 in ls blocks that have had p72 and pr3 heads on them and menny have bin milld if the cams are digryd right and the tuning is dun right you will have no prob at all

 

You're comparing Apples to Oranges on this one, Bro.

Comparing what you can run in a K-Series head to a B-Series head is MILES apart, man. You can't go looking at K builds to get ideas of things to do to a B series engine. The B Series combustion chamber is nowhere close to as efficient as the K.

About your question, this has been BEATEN TO DEATH on here, seriously.

PCT pistons + P72 Head = possible piston to head contact

To be safe, you'd need to run a thicker headgasket....but WHY? The ITR piston is a better design, anyway. Big domes DO NOT = big power. You have 2 engines with all things being equal with one gaining the CR from big domes and the other with a flatter piston (same CR), the flatter piston will create a chamber that will breathe better, and will have better flame travel across that piston.