Published On Feb 12, 2023
This is a test of rocker arm ratio, to see how accurate the advertised ratio is.
Tested are, GM Performance, Scorpion, Crane, and OEM GM. The tests were performed on a SBC Chevrolet, with a minimum of 3 trials to prove accuracy.
The results will surprise you.
Today, March 16 I have just published a follow up video where I measure the valve lift at every 10 degrees of crankshaft rotation from -20BTDC to 106 degrees ATDC, the full sweep of lift. I then calculate the average lift over the entire cycle.
Best to worse is a difference of .046" average lift.
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