As I mentioned in a previous post, I think I am going to add a pair of GM Vortec heads to my Chevelle's 355. I did a search to see what machine work is accepted well to these heads, and saw a sort of mixed response as some said machining actually was a bit detrimental to the performance. Can anyone help clarify this? I plan to machine any head I buy to get the most out of them if I can, so if machining Vortecs is 'wrong' should I go with something like World S/R Torquers or World Sportsman II? Also, I may look at a local salvage yard or machine shop to see by chance if they have any new, good Vortec heads for a little bit cheaper (only 17 and work like 2 hours a day, quite a budget), and was wondering if there are certain castings of Vortec to look for, or if they're all the same. Thanks for your advice.

What do you mean "machining"? Do you mean porting? They respond to porting, you just have to por them correctly. As for actualy machining, theres nothing wrong [actually needed for higher lift cams] with cutting down the valve guide's, putting in screw in studs, or bigger valves.

Taylor-
Like the above post, I can't think of any machining that would be bad for the heads...if you want to port them, just work the bowls and nothing else unless if you are a professional.

I've got a set of Vortec heads that I think I'm going to sell with a polished RPM manifold, but I don't know how much I want for them. Email me if you are interested. I would include the specific GM gaskets, rocker arms, and valve covers. Basically bolt on and go.

This past posting on Vortecs may answer some of your questions...

http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=4;t=013898