Originally Posted by flyingputz
Tomorrow I'll measure ALL the valve tips on my old, bad set of #906 castings. I KNOW all those valves are the original parts. Sometimes I think "The General" just uses whats available! Especially if it was assembled on a Friday afternoon! BTW, the (my) short-tipped valve HAS the backcut. What I DO know is that for MY particular application I need the .290" tips. The carmakers sure don't make it easy, do they? Oh, and Happy New Year!
It's not as bad if you need intake valves bigger
BTW, if you use stock diameter springs you might want to use the stock Vortec retainers- they're made to have plenty of clearance for self aligning rockers.
BTW II, all I have been able to find regarding replacement Vortec valves (or more correctly, valves used w/self aligning rockers like Vortec and LT1/4, etc.) is:
Intake- 0.260" groove to tip length
Exhaust- 0.289" groove to tip length
Why exhausts are longer I cannot say, but the first time the intake valve tips are reground, that extra 0.010" is all but gone. And as I said earlier, this is not like my Vortec valves- they're standard length tips. So take it for what it's worth- all I can say is a stock 0.250" tip is plenty for use w/the stock valve train.