Registered: Wed Nov 29 2000 12:00 PM
Loc: Central IL, again
Man what a blast from the past! I bought a 66 C10 longbed Fleetside 250 3-speed back in 78 when I was a pup. Great little truck!! I should have kept it. Traded for a Chevy LUV Sorry, I don't know how to tell. I guess it would be by the stamped serial numbers and casting numbers.
Registered: Mon May 08 2006 12:00 PM
Loc: DANVILLE IL
On a '66 I'd think it would be an SM326 if it's still the original. I'm not sure about #'s, but 1 way to tell is by the 1rst gear. SM318/319's have a slider gear for 1rst/reverse. The 326 is full syncronized. The case is longer as well. Can you post a photo? We can tell for sure that way.