Are you still using the original rear end too? as I would have never thought they would last a day behind a V8. I tore one up with a 235 and since replaced the original 3 speed with a T-5 and a Ford 8 inch rear end,you might also look at the 49 to 54 car trans as they go togather like the 37/38 3 speeds. I used a motors manual 49-54 trans section to help me go through a 38 trans and since disassemby and assembly process is the same the parts might be similar too.