I hae a 268h cam with a lift of .477/.480" as per the cam card. I was told by a local machine shop that the limit is .475" and that since i am close I could get away with a aftermarket spring retainer and that will be nough to clear has anyone heard this before?

 

Sorry but he's incorrect. The max lift of a stock Vortec head is 450. Use this as a reference.
http://www.sallee-chevrolet.com/Cyli...ads/Vortec.cfm

I do have information some where that says if you simply change the valve seals, you can get much more allowable lift. But the only way to be sure is to have the spring pockets machined.

 

Lots of Vortec info here: http://www.nastyz28.com/forum/showthread.php?t=56505

 

I have heard that cam before and the sound is alot better than the one that in my 330 hp crate engine but only a few more horse I dont know if i want to spend the money on the springs and my time.