Shorter stroke in 477, enough that you can probably measure using a wire or small dowel through a plug hole:
Quote from another post here:
"""You asked for it, from the Motors Truck Repair manual (C) 1979.
'66-72 477 - 4.5 x 3.75" 7.5:1 4 bbl carb HP:253@3400, TRQ:415@2300
'66-72 534 - 4.5 x 4.2" 7.5:1 4bbl HP:266@3200 TRQ:481@1700
In '73, they went down to 7.2 (477) and 7.3 (534) compression and the numbers went way down because of "net" hp/trq. In '75, there is a 475, same bore/stroke as the 477. The 475/477/534 were used up until '79, the end of my book.
Quick edit: there was a 2bbl 477, early on, in '66/'67, with HP:231@3400 and TRQ:412@1600 """
Which was from this thread:
https://www.ford-trucks.com/forums/1...ial-555-a.html
Somewhere here are all the bore/stroke specs + more for the 401/477/534.