Mopar34 - Thanks for the information, I'll look up the casting numbers on the heads and refer to Mortec.com to figure out what I've got. (I have to admit, I didn't think of looking for a casting number on the heads.) I'm sifting through a garage full of auto parts and auto related stuff for the widow of a friend. I'm a, dare I say it on this forum page,...a Flattie guy and my friend was a street rod guy, both hopped up Flatties and SBCs. I've identified an engine as a '66-67 283. It has vette valve covers and powerglide tranny. The fuelie heads are sitting off to the side with a new Edelbrock intake and other speed parts. I have no problem sifting through the flattie parts, but I'm lost when it comes to the SBC & speed stuff as we try to sort and sell it all off. Thanks for the info,...it has helped.