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Old 01-24-2008, 09:56 PM   #5 (permalink)
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Well I did just about the same thing to my sbc, not 1.3 rockers, but I did put antipump up lifters under the intake pushrods. Obviously this lowered the valve lift at the lower rpm, and I have a running dispute with another motorhead as to whether the effective duration was shortened.

The compression at the low rpm increased, quite similiar to advancing the cam. If you look at the xfi cam thread it speaks of lower lift, peak torque at a lower rpm, and smoother idle. I do know that going with higher lift and more duration( more overlap) lowers low rpm torque and raises the rpm that the power range and peak hp occurs.
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