Vortec l31 valve guide machining?

[yodertoter]

Okay guys I'm putting a cam in my 1996 gmc k1500 with the 350 L31, does ANNYONE know how much you need to machine off the guides to run a bigger cam???? Cam is .471 intake .502 exhaust. Yes I'm doing screw in studs and valve springs just need to no how much to take off the guides! Thanks!

 

[Parentnoia]

Out of the box, 0.480” valve lift, 350-400 HP dependant on the CR, cam, ring seal, oil control, etc.

More than 0.480” lift cut the guides down to clear the retainers.

Generally speaking, Vortec's stall at between 0.500” and 0.550” valve lift. This is where flow actually begins to decrease. But their true strength is low lift flow which gives more area under the total flow curve. And if you think about it how long are your valves at peak lift? They spend much more time at 0.400” and below, where the Vortec’s outperform most other heads.

That's the information I use.

If you're feeling brave, just see how much total you can cut off and go that far, that way if you ever upgrade again, you wont have to worry about clearancing them again.