Your vin number begins with C, then either an E or S. Those Id Eight or Six.
68's still used the 420 transmission, 69 introduced the SM465&435.
If the glove box lid is still there, the paper "Spid" will have the opted motor it came with. 307 was the standard 8, not shown, optional 327 would be on the spid sheet. A 250 was standard,not shown, optional 292 would be on the glovebox spid
