I have tohis old truck on my property that someone told me had a 454 or a 427 chevy bb in it. As it was a swap and not origional motor i cant look up the records. The engine compartment is cramped and the only numbers i could get were on the intake. The firing order is 18436572, which is standard for all chevy sb and bb engines. the engine casting number is 346260. Jut below that number is a 10 and a OM or MO. Any ideas?

-Nick Meyer