Using Harland Sharp 1.65 rockers ?
If so, keep in mind their actual ratio when calculating the valve lift.
We have seen it stated the Harland Sharp Pontiac 1.65 rocker arm ratio to be 1.7, 1.72, etc.
One example. Years ago Ken Crocie used Harland Sharp 1.65 ratio rockers on a build.
The cam had 0.3600" lobe lift and based on 1.65 ratio it suggested a theoretical 0.594-inch valve lift. Yet when measured on this specific build it netted an actual 0.606-inch lift at the valve.
Here the actual ratio of the Harland Sharp rocker seems to be closer to a 1.684 ratio. This was a static measurement A running measurement 'at the valve' could be different.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 )
Old information here:
http://www.hotrod.com/articles/0712p...tiac-trans-am/
Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
Best time 5.13 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE
Last edited by Steve C.; 10-21-2025 at 04:38 PM.
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