308/Auto Trans Configurations

While reworking a 308 for my 52 Hornet I have been given information on the various options that exist. I feel I should summarize and share this info as it will help others figure out the pieces of the puzzle.

a. Basic configurations are 51-54 blocks & crankshafts, 7/16 headbolts, and cotton yarn type rear seals, oil dipstick behind the starter. Crankshaft forging number is 304668 (found on the lobe behind the second main bearing) and the rear mounting area for the flywheel is about 3 1/2" diameter.

b. 55-56 engines and crankshafts, 1/2 headbolts, neoprene rear seal, oil diipstick in center of engine. Crankshaft forging number 5325009 with the rear mounting area for the flywheel is about 4 1/2" diameter and they are 1/2" shorter at the rear mount than the 51-52 cranks. The crankshaft was changed to mount on the larger shaft. To use this in a 51-54 automatic a 1/2" spacer must be used between the crankshaft and flywheel or replace the crankshaft and flywheel with one from a 51-54,

c. In late 54-55 Hudson offered "replacement" "Crate" "JC Whitney'" complete engines with all accessories. The ones I have (2 of them SNs 5320963 and 5321340) have a 55-56 block and a 51-52 crankshaft and the oil dipstick is behind the starter and will work in the 51-54s. The crankshaft and flywheel would have to be changed to work in a 55-56.



Oil Pans, front and rear plates may be different and will have to be matched for the correct application. Oil Dipsticks may also have to be modified. There are also 55-56 engines out there that have all ready had 51-54 cranks placed in them.