Thread: Vortec heads, what casting not to buy

Tweet

I have a chance to purchace a pair of Vortec heads and remember a post listing casting numbers to stay away from. Maybe I am dreaming but any help with casting numbers will be appreciated..

Thanks,
Garson

High Performance Chevy's latest magazine that's 70% about blowers this month has an article on the newest & latest vortec heads. When I get back to the dorm I'll look up the casting numbers. Those are the ones you WANT. I know I WANT them

From the web site www.sallee-chevrolet.com

QUOTE Please Note: The casting number myth debunked:
The myth is that there is a difference in the head performance produced by these two castings.
This myth was started by some Magazines that didn't do their homework before publishing their articles.
This is the truth the whole truth and nothing but the truth. So sayith the Grand Wizard GM and his Apprentice Wizard GILBERT CHEVROLET.
10239906 casting has one large single hump.
12558062 casting has 3 small humps.
If either of these two castings have not been altered by GM and the part number changed from 12558060 or altered by someone else (previous owner, etc.), the heads produced by either casting will be identical except for the external cosmetic difference. Both castings are used to make the 12558060 Vortec heads which are the true unaltered Vortec heads.
Heads from both castings come out of their cast IDENTICAL except for the minor cosmetic external differences!!!!!!!!