anyone links to vortec head swap/ limits on valve lift. modifications??

[crossy]

anyone, links to vortec head swap/ limits on valve lift. modifications??

I currently run a 507 lift cam with lots of duration and i dont these stock 906 heads will take that without modifications ?? DAVE

[Prerunner1982]

I think .450 is about it, but Scoggin Dickey has a set that can take .550 and another one with .570 .

http://www.sdpc2000.com/catalog/2172...-Head-Kits.htm

[84slopwaggin]

You can't beat a set of these from summit.

http://store.summitracing.com/egnsea...lse&Ntt=151124

[crossy]

OK that gave me answers about lift now I need the right parts to make mine safe for 500+ lift. I bet SDPP uses stock GM Lt4 parts ???

Has anyone used these on a TBI to really feel the results.

[Jonboy]

I think there was an article on the Chevy High Performance website about modding the heads for higher lift. Seems like they used an aftermarket "beehive" type spring, IIRC.

[Zoomad75]

The key is machining the valve stem guide bosses for clearance. The issue is retainer to guide clearance. A good machine shop can machine the guide bosses down to accept aftermarket PC seals. At the same time have them machine out the spring pocket to standard SBC size and then you can run whatever kind of SBC sized spring you want. The beehive springs mentioned in the magazine article are trick but high cost. Being able to use springs for a *standard* SBC (non-vortec) will still cost less with machining than the beehives will. At least then you can run a spring that the cam manufacturer recommends.

My Dad had a set modified by a local shop in Denver for $100 to do the pair of vortecs I gave him. Cut the guides and the pockets and installed Z28 spec springs. His cam is pretty tame (.448 lift) but he wanted to be safe. On the other hand I have a buddy running unmodified Vortecs in his S10 with a cam that is right at .500" lift. How he hasn't smacked anything I don't know since that poor little 350 sees 6 grand everytime he hits the street with it. I'd say from all I've read on the vortecs is to machine the guides for clearance when you are running a cam with a lift # of .490" or more.

Just check around to the local machine shops, it's not hard for them to do. Or you can get the tool to cut the guides out of Summit and do it yourself.