Ok, I'm new to the forum, and have the most basic of questions. The numbers on my block are ECZ 6015 C. I have been checking John Mummert's web site and he ID's this as a 312 or 292 with EBU main caps. How do I know the difference, and what are EBU main caps? I have also been checking the heads and find no ID on them in the usual places. This engine came out of a 56 F100 (not the truck I have) and it is not known if it is original.

Thanks much.

Wally