My Hollander interchange shows three different Kaiser Frazer blocks. #121 47-48 with rear fuel pump, #122 47-50 with front fuel pump, #130 51-54. Hydramatic and manual trans blocks are the same. There are three different KF cranks. #191 47-50 , #548 51-54 manual trans , #567 51-54 Hydramatic. I don't think you can put the 51-54 crank in the 47-50 block or visa-versa. However Hollander says you can use the complete 51-54 manual trans engine in the 47-50 if you use the 47-50 front mounting plate and water pump. The front and rear fuel pump blocks will swap with each other but is more work.