What's the general consensus on using 1.6 rockers on a SBC with a single pattern cam and GM casting heads? Use them all around or just on the exhaust valves?

This has been debated here several times, and it seems to depend on the engine. Many have put them just on the intake, and it helps. Some have put them on the Intake and exhaust, and it helps. Some have seen no improvement at all or very little. If you have a set of headers, since the exhaust gas is pushed out, you may not need them on the exhaust. On the other hand, if you have a restrictive exhaust, they may help. Alot depends on the Heads, flow, cam, etc, so it's ends up being a try it and see what happens. Remember to check for proper clearance on the valves, as you'll be adding a bit of lift.

Fred.

I'll do some more searching then. Sounds like it's a hit or miss deal.

Thanks

Think of it as a tuning tool; in the same class of things as jets or timing.

You will almost never "hurt" performance by increasing valve lift too much. That is to say, the car is very very rare, that will run faster with 1.5 rockers on either valve than it will with 1.6s. What you DO gain, however, may be reliability, and freedom from valve float; if your head ports flow well at the lower lift, you may find that either your springs last longer, or you get a few more RPM, with the lower ratio rocker.

Head Flow Numbers:

0.050--Int. 40.4 Exh. 29.5
0.100--Int. 71.2 Exh. 57.4
0.200--Int. 137.9 Exh. 107.9
0.300--Int. 165.1 Exh. 127.6
0.400--Int. 191.8 Exh. 139.5
0.450--Int. 204.7 Exh. 144.2
0.500--Int. 205.8 Exh. 146.6
0.550--Int. 214.9 Exh. 148.8

Spings are .600” Lift Double Valve Springs. Specs on them are 125lb Seat/325 Open PSI, 1.800” Installed Height, 1.250” Dia, 1.110” Coil Bind.

Cam is currently 292H, .501/.501 lift w/ 1.5 rockers.

I plan to have 2.5" exhaust after everything is all said and done.