I ran the original made in Australia EQ heads with the standard length 4.92” valves using this kit from Hughes Engines. Ran an Isky hydraulic (with 1.6 rockers) that calculated to .517” valve lift. The springs are good for lift up to .540” Just keep in mind that’s calculated lift. Actual lift will be less due to angularity loss in the valvetrain. I had no valve seal to retainer clearance issues. They were a drop in deal, still need to check clearances though. You could piece together the parts needed likely for less. Maybe someone here has that info which might be a good option
