Hey guy's I have a set of heads I want to have redone and put on My Demo derby Motor I need help figuring out if they are a matched set and what size valves they have in them.Any help would be greatly appreciated. The numbers off of them are Left Side 3973487 also C101 & GM27. Right Side 3973487X also A132 & GM27 Once again any help would be appreciated thanks. Jacob
03-15-2007 09:00 PM
Re head Numbers
Hey guy's by the way these are off of a small block Chevy Thanks Jacob
03-15-2007 11:24 PM
Most of the 487x heads i seen came off the 71 LT1 corvette 2.02 x 1.600 valve.
03-16-2007 12:07 AM
ya, a kinda rare head, not really for a demo derby car, no sense in cracking them if the rad gets busted