kaiser supersonic head

i am a newbie.

just acquired a '48 willys, w/ a supersonic head from kaiser.  (serial no. 741422, ... , must have made several of them, eh?)   i wrote to inquire about it, posted at a place i wasn't supposed to.  "read the notice," a subsequent (private) letter said, to spare me the embarrassment of publicly telling me i'd messed up, and they replaced the post in a general "discussion" page.

anyhow, a person came on and told me that the numbers "6410" in the casting numbers indicated a latter date replacement motor for my '48 from willys, and that the supersonic head was didn't start manufacture until the 1950's, perhaps 1953, and from kaiser.

it is indeed a "performance" head, by the simple expedient of shaving about 1/8" from the bottom, and therefore decreasing the combustion chamber and raising the compression ratio from 6.48 to 1, to slight above 7 to 1.    this added about 5 horsepower, a not inconsiderable amount in a 60 base horsepower motor.

(this i read somewhere else, and somewhere else they have pictures of the resultant size and shape of the combustion chamber.   i don't have the link, though i saved it somewhere.)

so, i have a replacement motor from willys, with a head from kaiser post-1953 manufacture.    neat.  cool, even.   

this is a very informative blog, and i like it.

john jay 

i think kaiser took a little off the bottom of the head, and added a little to the top, to make up for it structurally.   at least, that is how the people who have commented about this (at other chats) described the raised ribs on top of the kaiser block, e.g., to lend strength for the increase in compression.

i never in my wildest dreams ever thought that a "simple little flathead" motor could have so many permutations.   it is all very interesting, to say the least.