Building a 77 motorhome 440

Id like it to be more to the tune of 5-600 hp though 375 is plenty enough for any application
In that case, you'll need a different top end for sure. Indy is one good way to go. 440 Source another. You might try contacting @PROSTOCKTOM here on the forum. He's a Molnar dealer and a fine fella. He may can get you a deal on a top end kit. I don't know. I'd much rather support a member here. I tagged him, so maybe he'll chime in. I know he can fix up on the bottom end.