Rhoad’s lifters really should not be needed on that combo with a current 60919 unless for some reason you wanted a more smooth idle and maximum grunt force right off of idle. Driving manors would be no issue at all with regular lifters. Original 3.31 gears sound like an a 12 bolt car with a 4 speed or a non A/C automatic. I would not expect any issue with low end power with that much compression in a 455.
On a Pontiac using a HFT cam with .842” diameter lifters of the same size duration as a RA4 type cam the 1.5 rocker arm cam combo will not be able to not have the same lift as a RA 4 cam with 1.65 rockers, the contact point of the lobe at the lifter will be off the edge of the lifter face. I am not sure what the maximum lift is for a 231* @.050” HFT cam is with a .842” lifter without making the lifter bigger, but it is likely a little less than .516 lift. The cam tunnel size also impacts the ideal rocker ratio, a bigger cam tunnel is able to run more lift than the smaller cam tunnel and more easily run larger ratio rockers.
More or less to compare the options equally the 1.65 rocker cam would need to have less lift. The bigger rocker ratio wins the debate most of the time before the debate even starts.
Last edited by Jay S; 03-22-2026 at 05:12 PM.
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