|
The early 50"s A"s and M"s are listed in the Nebraska test as having about the same drawbar hp;34. The A has a 2.5 mph low gear and the M has a 2.6 low gear. My observations are that both the standard A and the standard M would generally kill on the track and not spin out. The M was easier to "soup up" because it was a sleeved engine and a four cylinder. A simple oversize sleeve gave a double increase because it increased both the displacement and the compression ratio. This is how the M became a super M. For the A, high compression pistons without the expensive process of boring the block did not increase the displacement on the A so the hp gain was generally less. The four cylinder engine was better balanced so increasing the rpm of the M engine 10% was generally without bad effects. Increasing the rpm of the poorly balanced two banger was less desirable. Overall, this made the M a preferred tractor to use to get heavy work done. The M Farmall, DC Case and 44 Massey had similar 4 cylinder engines and could quite easily be tuned to significantly out work the A John Deere.
| 
