Panic, to respond somewhat to your questions regarding different heads, the 848 head that I was originally running developed a crack and had to be replaced this past year. I replaced it with another 848 head and so with two different heads, no interference. That being said, it looks like there is enough meat on the head and block to drill the push rod holes slightly larger, sort of like what is done to use 3/8 push rods on a 250 and 292 head except because of the ball and cup arrangement, the 235 and 261 motors would not need guide plates.
Last edited by Dragsix; 02/23/2022 10:11 PM.
