Hi Ken,
Look up Ryan9815, he's on the board here. He is doing the same thing as you with his 63 Nova. He's also here in California.
I'm Chris, near Sacramento.
This is from:
http://www.thedirtforum.com/ubb/Archives/Archive-000001/HTML/20040201-20-000279.htmlLots of Chevy casting numbers and descriptions here!
1967-72
250 CI
4.1 Litre
3.875 cyl bore
L-6
7" from Rear Dipstick
2 Bolt Starter.
3850817
3854036
3877178
3994257 <-
3927763
3895052
3876802
3621
Here's one of the comments I found while searching.
"Help.. am trying to assist a friend in decoding other GM 6 cyl casting numbers. He has an engine out of a 1968 Pontiac Beaumont ( like Chevelle) which has the block casting number 3994257 . We have looked at a number of sites online but have not found anything. Can anyone confirm that 1) it is a Canadian engine.
2) what the displacement is. 3) what the year is... It is attached to a Powerglide Tranny."
From:http://corvaircenter.com/phorum/read.php?1,111125,111291
In the forum under "Other Chevy 6 Casting Numbers "
Maybe it's from a Poncho,from north of the border. That would be Cool.
Good luck with your project!
