Nice build. If It was mine I would put bias tires on it. That rounded radial tire look isn't right on a sixties car.
I would also put a period correct T-10 trans and the original style crossmember and trans mount in it.
I do have a 63 catalina 2 dr factory 389 tri-power 4 sp, 63 bonniville 4 dr ht, 63 catalina safari amblewagon(factory amblance package but no raised roof, HD susp, big alternator,HD cooling),63 catalina conv. build-it project. was 389 auto. Have the parts for 421 tri-power,4 sp,fac air, PS,PB,tach,8 lugs,ventura int. tags. Someday.