Thanks for your help. My 235 (1952 1-1/2 ton) does not have the two acorn nuts but rather four bolts that secure the valve cover around the outside flange. So I guess this means that my 235 is for sure high pressure and not original to the truck. (this truck ran until 10 years ago.)
How can I find the year knowing the block number off the engine adjacent to the distributor?
