I have swapped to an 848 head now, but for whatever reason, the engine I pulled from my grandfather's 1 1/2 ton did not come with the 848. Glad I ended up with the optimum swap in the end! (Although I do need the temp sending port adaptor) Additionally, I inadvertently found out about the neoprene rear main seal, so thanks again. I incorrectly had the old rope seal in my head.