i have a 54 5 window with original motor and everything but i was told that that motor cant hold up to daily driving and i should put a 350 in there it will fit just fine. i dont know much about mechanics but i love old trucks specialy chevy my uncle sold this one to me couse i wanted it since i was like 10 but he lives 5 hours away and cant help me much he said to take it to a resto shop and let them do all the work since its more than i can handle but id rather try to do some of the things myself id like to start with the motor and get it started first then work on the body if im doing anything wrong please let me know i really dont know anything but im enjoing myself trying to figure it out and im up for the challenge