George Wright

Quick question:
I have several sets of 3731539 heads; Some of these have an X cast into the side, others do not.
What is the difference?
Tia,
G

George Wright

Found the answer----the X casting on the exhaust side of the 539 heads were late production---no other difference.
Did not learn why?

jimgessner

Al Colvin says ''Was used only in 1957 on 283/220hp, WCFB four V carb, Passenger car and 283/283 solid lifter Corvette engine. It was identical to 3731554 passanger 265 head except in combustion chamber and valve guide boss''

''X'' code appeared on 1958 head #3748770 used on all passenger and Corvette high 230 and higher hp.

I have never seen a ''X'' 3731539 heads.

George Wright

Jim,
I got the info from the NCRS site.
These came from Dave Ewan's collection.

oldskydog

I have seen a number of late 57 539 castings with the x. Probably indicates a change in metallurgy in the casting material.

jimgessner

What are the dates of the 539''X'' heads? I think it may have been an added item getting ready for 1958. Could you send a photo?