I just got through putting a Comp 232/236 595/601 on a 112+2 XE-R in my mostly stock Firehawk. My Question is with stock heads running dual springs rated to 650 lift will I have any problems with PVC. I don't think my sponser would have sold a cam that would have that problem, however I thought i would ask. Stock heads......not milled....stock rockers. Thanks

 

You will be ok.

 

You should be just fine. But just so you know, lift has almost nothing to do with PTV clearance.

 

That shows my ignorance. Is it the duration that causes proplems?? I just know enough to follow the instructions on the LS1 How To pages. Thanks

 

Yes, duration is a big factor. You usually only have to worry when you start milling the heads, using aftermarket valves, and getting thinner head gaskets. Once you do that to attain whatever compression ratio you want, then cam duration becomes really important because with too much duration, the valve will be left open too long causing ptv contact.

 

Here's a good visual for ya. Emagine the valves staying open longer as the piston comes up and down at the same rate. Eventually, with too much duration, you'll have contact.

http://static.howstuffworks.com/flas...ft-pushrod.swf

 

Technically it has nothing to do with lift or duration. It is valve event timing, i.e. lobe centerlines. The closer to top dead center your pistons are when the valves at at max lift is the problem.

 

Do you have any dyno numbers on that cam? Sounds like a pretty nice grind.