There is a machined pad immediately behind the distributor with a stamped, not cast number on it. You might have to scrape a little crud and/or rust off of it to read the number, and if you rub a bar of white soap like Ivory or something similar over it, then wipe the flat surface off, the numbers will really stand out. Post those numbers, and someone here can look them up. The block casting number is near the front of the engine ahead of the fuel pump, down near the oil pan rail.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!