This is what i got. This is what i wanna put in it. Any advice would be appreciated

You need to get rid of the parking brake tail stock on the trans and the exhaust manifolds will not work, there’s more to the list but I’m 100% sure other people will have their “opinion”
440-3 motor motor home engine has heads with zero performance potential, standard big block heads will fit with the correct gasket. Not an "opinion", but a fact