I have a set of heads that have casting # that end with an X has anyone ever heard of this i can seem to figure out what it means. Thanks

http://www.mortec.com/castnum.htm

Everything you ever wanted to know about chevy block & head casting numbers, but were afraid to ask.

There were about 8 different "X" casting heads, some good & some crap.

What are the 3 digits before the X ?

-461x and -441x to name two..

pdq67

thnx for the help the heads were nothing special.