I'am doing a cam swap on my 84 Z-28. It has a 30 over 350 in it with L31 vortec heads. I have been told that to be on the safe side that I should cut down the valve guides because of retainer to guide clearance. I have acess to the tool to cut them down with but don't know how much I should cut off them .030 or .060 or what, i'am going to use the teflon seals, and the max lift in the cam will be 480. If there is anyone out there that has done this or knows how much to take them down, I would realy appreciate some help. Thanks NORT

[This message has been edited by NORT (edited April 18, 2001).]

 

I had my vortecs machined. If you take them to a machine shop they can measure how much they'll need to take off or you can call Comp cams and they will tell you. I am putting the extreme 268 in my 350 with 1.6 roller rockers. My lift should be .508 .512. The guy at the machine shop says that there will be no clearance problems. I can't wait to get the stuff on my car. Hope this helps.

 

did the guy at your machine shop say that after you had the valves cut or before because I am using the same set up and I did do anything to my heads yet (there still in the box) sorry if I miss understood.

 

It doesn't matter if they machine them before or after getting the seats done. The valves have to come back out though....

 

I am running the HOT cam with the Vortec heads and 1.6 rockers-.525 lift. I pressed the stock seals further down on the guides, machined .030" off of the bottom of the retainer and have been running ever since. 3000 miles so far with no problems.