Beginning with 1958 passenger cars, there were three bolt holes on each side of the 283 block beside the #3 and #4 cylinders, for mid-engine motor mounts. At the same time, the mounts at the bellhousing and the front of the engine were eliminated and a mount was added at the rear of the transmission. If your block has those three holes and a place to attach the oil filter at the driver's side rear of the block, it's the mid-60's 283 that the engine number suffix indicates. A 1955 265 with that letter code won't have an oil filter mount or side-mount bolt holes, and the early 283 won't have holes for side motor mounts.
Truck engines kept the 4-point motor mounts at the front of the engine and the bellhousing through the early 1960's, even if the block has holes for center mounts.
Jerry
Edit: Drop me a Private Message with a phone number or an email address, and I'll be glad to look at the engine and try to help identify it. My farm is actually about 60 miles south of Nashville, but I'm up that way frequently.
Jerry
Last edited by Hotrod Lincoln; 10/20/2011 3:07 AM.
