Magnum heads convert to sbc rockers?

gregsdart said

Thanks for the input everybody, I will consider the Hughes deal , as it looks to be about the best considering cost versus what it offers. One possible change though on cam choice. Two reliable sources are using other brands, less radical ramps allow more stable rpm before lifter pump up is what I was told. The dyno operator I plan to go to said the Voodoo cams have fairly radical lobes which on some of their dyno sheets show them having less rpm potential due to lifter pump up. He said they saw instability as low as 5500 rpm. So,, A Muther thumper looks like a winner. The right .050 specs for what I want, and ought to be stable.

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Hold the phone there...... this really bothers me. Did they explain why the lifters pumped up? (Do they even understand why?) The ramps are a contributor but not the real casue. Float happens only because the other valve train parts are too heavy or the springs are too weak or instable to keep the valves from floating a bit at those RPM's. OR the rocker geometry is such that is is causing large speed variations in the valvetrain acceleration or deceleration. I am have to ask if the dyno operator ever explored that or recommended any corrections. (And some dyno operators are just that... operators..... not builders.)

The correction to this is NOT to change cams from what is best for the application, but to fix the valvetrain issues.

I don't think much of the mutha thumpr line; it is for the noise, not the go.