The '68 J Code Cougar I am restoring (built in SJ in Dec 67) still had the factory exhaust when I acquired the car - mufflers stamped with FoMoCo logo and part #s C8WA-5230-A / 8-31-67-A and C8WA-5232-E / 11-7-67-A. Not sure if I will restore these for re installation, but have been told by various people that they are desirable. Can anyone tell me 1) why the part numbers are different (assume the second number is a mfg date?) 2) whether these could/should be restored and reinstalled (is it cost effective?) and 3) if these would have value to someone doing a true concours restoration? Thanks.