[383vette]

I would like to use a 1.7 roller rocker on my sbc. But I have heard that this can increase valve guide wear.Why is this true if it is a roller tip.

Tech. info: heads eldelbrock performer rpm.
cam. comp cams mech. flat tappet. 250 deg. at .050 intake. 262 deg. at .050 exh. with .571 gross lift intake, .595 gross lift exhaust.

I have had the heads ported & 2.055" intakes installed. They keep increasing in flow untill the retainer & rocker arm would interfer at .790".

I have mocked up the piston to valve clearance with 1.6 roller rockers & have .195" p.t.v. clearance.

The spring pressures are 125# and good to .670" lift.

Thanks,

Jim

[engineguy]

I don't know if you will be able to get a 1.70 rocker to work on a SBC. In order to use 1.60 and 1.65 rockers, you need to elongate the pushrod hole in the head. It would be real tough to hog out enough material to put a 1.70 in there. Why not just get a cam with the lift/duration specs that you desire, with 1.50 rocker ratio??