I have finally finished the melding of two kits, an ESCI M4-A1 and an Hasagawa M4-A1-E8 in 1/72nd scale. I addition to adding changes to the turret for the counter weight, the gun mount and the loaders hatch. Changes to the hull included a new intake, large storage box on the back and, lots of little pieces(fuel cans road wheels, back packs.
Youir M51 looks good . Who’s kit is it and what scale ? You mentioned an M1 /M1A1 ?