The six ratio is 7.5 to 1 & the big block is 7.0 to 1. When I had the cam ground for my 153 four cylinder we took that into consideration so I could use the BB roller rockers that I had. Even with the Mercruiser cover you may need a spacer and to round the corner on the end rockers, not sure. I think anything that reduces stress on the valve train is good. I don't know how they would effect pushrod length or if pushrod guide plates are needed.
Last edited by Beater of the Pack; 11/18/21 11:35 PM.
