350? Heads

Can anyone tell me if they are 350 or 340 heads? Here's the numbers

GM 10
M 13
R-1376330-K

A guy at work wants to build a set of 350 Stage 1 heads out of these. Where can I get a book with #'s for Buick motors, both big and small block?

Thanks,

P.D.

 

http://www.atlantabuick.com/CastingNumbers.htm

http://swapmeet.ca/codes/buick_smallblock_casting.html


http://buicks.net/shop/reference/smallblock_casting_numbers.html

The closest number I could find to yours is:

1366379 - 67 340

 

Thanks!

Thanks Adam for the links and info. The valve covers say 340, the air cleaner says 350 and its a '69 Special Deluxe 4dr. I'll have to blow the dust off of the vin and find out what it's supposed to have.

P.D.