I had an idea a while ago to do an upgunned Sherman for my Yank army inspired by post war Isreali Shermans (M51 Super Sherman) I know that there were some experiments by the Americans at the end of the war to upgun the Sherman with the same 90mm gun used in the Pershing, so this is what Ive settled on - M4A3E8(90).
Here is a work in progress shot of the turret with the 90mm gun (got it from China, its metal) and IR searchlight.

The barrel next to it is the original 76mm from the Kit (Hobbyboss)