Don't know if this helps or not, but my parts book only has two different casting numbers for the 265 engine...3703524 (55) and 3720991 (56 & 57).
The 3731548 casting number in my 1959 Parts Book is listed as "57-58 PASS., CORVETTE (F.I. /w H.L. Cam)". Cubic inches are not listed for this casting number, however this would not be a 265, they never Fuel Injected that engine.
Mike B
