Originally Posted by flyingputz
Oops... I meant 4.91", NOT 5.91". Thats the plan Mousefink. The Manley race master intakes. I may not have to use the +.050 locks with them being that they're .050 longer. $119 for 8 @ Summit. Thanks.
If you budget can take it, use Manley 4.951" intake and exhaust valves with .290" tips. The reason the GM Vortec intake valves have .260" tips and the exhaust valves have .289" tips is because the intake valve margin is .050" and the exhaust valve margin is .080". That makes the intake valve .030" taller in the head.
My machinist uses a Serdi valve grinding machine and the finished intake and exhaust valve tip heights were identical using a .050" intake valve margin and .080" exhaust valve margin. When I picked up the heads at the shop, the first thing I did was to place a steel straight edge on the valve tips and all valve tips touched the straight edge. There is no reason to use +.050" locks with the Manley valves if the valve seats are ground with .050" intake and .080" exhaust valve margins using a Serdi machine.
I furnished a set of +.050" locks to my engine builder in case he needed them to use with shims in order to eliminate the exhaust valve rotators and achieve 1.750" spring height. Standard Vortec spring height is 1.700" . He eliminated the rotators with .090" Alex's Parts hardened valve spring shims without using the +.050" locks.