I need to know how much i need to grind down the boss's on my vortec heads to handle a .550 lift setup. Im installeding .550 springs and roller rockers to handle the bigger cam but i need to know how much i need to grind down? thanks

may i ask what type of cam you are planing on using?

crane powermax cam

why are you trying to use such stiff springs with a hydrualic cam?

well the stock springs are coil binding. The exhaust lift is .494 sould i just go with a .500 lift spring?

yea id try to .500's just because a cam has a big lift dosent mean you have to have a killer spring, if you get too stiff it will collapse hydraulic lifters, if you wanted a big lift cam youd be better off with a solid cam, but for what you are doing i think the .500's will do

k...u know how much i need to grind? cause the machinist needs the specs and such

i would email the guys at gmgoodwrench.com ask them about the valve springs too just to be safe but i think the .500's would be fine

Someone at Scoggin-Dickey could probably tell you how much they remove for their .525"-capable Vortecs.

www.sdpc2000.com

If the machinist cant figure that out for himself whats he doin?

You can easy figure it out yourself or tell him how.

Mock it up by installing a valve with seal you plan on running put the retainer on and measure the distance between bottom of retainer to the seal.
If youre going to use an all teflon seal measure the seal portion that is above valve guide when installed I think its .250 (havent done one for awhile) and subtract that from retainer to guide distance.

If you use a Z28 spring that is just about right for those heads with a cam with the lift you are using. That is what Scoggin Dickey uses in their heads made for a higher lift cam. The cam you are going to use is just about perfect for the vortec head. I had a Comp Cams xe268h cam in a 355 with Vortec heads and use the Z28 springs and it worked great. That cam has .477 .480 lift which is similar to what you have. As someone else said, scoggin dickey can give you alot of good information if you call them.

good luck,
Adam