Best Place To Look Up Engine Numbers

[dirtfarmer22-250]

I just bought a 454 for my 64. The motor is complete and when I was looking it over, saw that it had HI PER PASS F8 on the back of the block behind the flywheel.I know what the HI PER PASS means but not the F8. This got my attention. I'll have to take a wire wheel to the serial number as the paint got a little thick and I couldn't make out the numbers. Any way, to get to my point, is there a reputable site that I can go to after I get the numbers or will I have to talk to the dealer to see if they would run the numbers. Thanks for any info in advance.