luxor

iTrader: (2)

I have read in these posts where some have run this cam without any head modification but for those who've had machine work done how much did you mill the valve guide bosses? I'am building a 350 and porting the heads at this time and I just bought a ZZ4 cam. When I send the heads to the machine shop for a valve job I figured I'd mill the bosses just to be on the safe side and knowing in advance how much to mill would help. Rather than having to assemble the heads mount them on the block and then check for clearance, disasemble and return to the machine shop.
Thanks in advance!

RB83L69

You shouldn't have to mill them at all.

But rather than measure it by how much to take off, instead measure how much you want to leave; leave just enough to put a positive seal on them.

While you're having stuff done to that exact place on the head, have the spring pockets cut for larger springs. Most racing head shops usee one cutting tool that does all of that in one quick step, so it doesn't cost any more to get it all done, than it does to get it done piecewise.

http://www.compcams.com/catalog/313.html

luxor

iTrader: (2)

Thanks RB83L69, That make sense, I'll just have him mill them down a fair amount but leaving enough for the valve seals. I already was planning on getting the valve pockets cut for larger springs. Thanks again.