Don't know cuz I haven't swapped them but the original one on
my
'50 and the original one on my '54 both measure the same. 30"
across the front and flat on the bottom, about 48" in a
straight line from the front to the back and both about 55"
across from a common point under the back across the firewall.
Sure looks to me like they would swap even up.
Like to hear from someone that's actually tried it, even
thought the parts book puts a break in at '53/'54.
I'll bet Tim L. or Brad A. have tried it.
Denny G