3880492 small block heads
 

3880492 Any body have any idea what theese heads would be off of I was told the casting date was W273 I questioned the daste but thats what he claims it is. They have the small double humps like the Z28 186 heads have and also the accessory bolt hole, they are not angle plug heads. thanks

Re: 3880492 small block heads
 

They are over_the_counter EXACT replacements for the 186 heads. There is absolutely no *visual* difference that I have seen. Mostly available after mid year '70 and on... I do know some dealers used these if they couldn't get 186 heads, for any GM warranty situations. HTH.

www.mortec.com

Jim

Re: 3880492 small block heads
 

Jim are you thinking 3991492s? I can't decode 3880492 to anything in my references. The common 3991492 would be the over the counter replacement heads available after 1970. They came in different valve sizes as well as straight or angle. John that number has got me lost. Is the head cast with "GM"?

Re: 3880492 small block heads
 

Darren, you are correct, brain fart.....wasn't paying attention in class... but I do have a few 3991492's around here

Jim