Join Date: Jan 2001
Location: Lubbock, TX USA
Re: 350 with 305 heads----swapping to vortecs??
Get a dial indicator to measure you current valve lift. You can upgrade the springs (HIGHLY recommended) and use a retainer that'll give you a good bit more clearance without having more machine work done. I've NEVER seen a Vortec head with a stud that pulled out on it's own, I think you're fine with what you have, particularly considering the price of upgraded Vortec heads. Sell the roller rockers and use that for the springs, etc. At that lift, they're not really doing you any good anyway.
If you have time, have someone massage out the ridge in the exhaust short turn. It won't take but a few minutes and will help a lot. I use a Fordham tool (a lot like a Dremel with the flex line) and blend the cutter marks out and do the short turn work on all the Vortec heads I use. It takes about an hour per head but IMHO it's worth it. You're not porting 'em, just cleaning up Chevy's machine work.
Your compression should be fine, it's low 9's with Chevy's dish piston or right at 10:1 with true flat tops. Plan fuel accordingly.
FCS Harmony Racing
Momma always told me not to look into the eyes of the sun.
"But momma, that's where the fun is!"