What do these numbers refer to?

I have the oportunity of buying two complete heads. I don't know what they'll fit. The numbers on the side are: 311.101.373A. Made in Mexico.
Will these numbers let me know what type of engine they're off?
Please, can anyone let me know what type of engine they'll fit, from these numbers?
Regards,
Mark:thumb

See these links:
http://www.oroad.com/volkswebbin/wall/technical/showmsg.mv?message=6127

and

http://www.geocities.com/glennsvwstuff/high_performance_parts.html

Looks like these are 1500/1600 SP heads.

hth

According to my records they were originally off a type 3,1966 model 1600 single port,used on Type 1-3,hey thats what it says!😉