Bought a motorhome with the 275 hp motor. Since it needs exhaust manifold gaskets I was just planning on putting on a HE351 now and probably some injectors in the near future. I had a K31 and a BD cast compound adapter laying around and mocked it up with the HE351 just for fun. Now I really want to do compounds. I'm thinking 40ish psi. My only real concern is the head gasket. What would be considered safe with a setup like this? I have read about people having head gasket problems but I am guessing that most of those issues are timing related. Being a 275 would this have a HO pump? From what I read the timing is different between the SO and HO pumps. If that is the case would adding injectors with pump with more timing advance be enough to cause concern? I really don't want to pull the head but definitely don't want to blow a head gasket while on vacation.