RAD5

I picked up a set of 906 Vortec heads with about 75k miles on them and I was wondering what machine work I should done to them. I was planning on having screw in rocker arm studs, and I want to use the beehive springs for lift. I know I need to have them checked for cracks but what else should I have done? Do I need to do anything with the valve guides? 3 angle valve job? I would like to keep my cost down as much as possible. Thanks!

Air_Adam

First, check em for cracks - especially between the intake/exhaust valves. They have a bad habit of cracking there. If they check out, then have the necessary machining done (planed if needed, valve job, new valves 1.94/1.60 sizes (thats a bigger exhaust valve, the intake is ok though as-is), maybe have the spring boss cut for larger diameter springs if you want, etc)

After thats done, then you can have them cut down the valve guides to accomodate a higher lift cam, and have the pressed in studs pulled out and the bosses machined down and tapped for screw-in studs, and guideplates if you want to but that requires opening up the pushrod alignment hole as well (no big deal).

RAD5

I was thinking of using the beehive springs because I heard a lot of good about them in regards to valve float as I am running a roller cam, and I saw a dyno test and they actually made 7hp more. I know the springs are expensive but I think it would be the same price as the machining. Should I have anything done with the valve guides? Should I have new ones pressed in?

Sonix

iTrader: (1)

Yea, new bronze thick walled guides are probably needed. They can check if you need it with a valve though.
Yes, you really need to have the valve guides cut for more lift. Get the shop to cut them down like .100" and make them ~.500". That way you can use off the shelf positive seals.