Well I gotta ask what B1 head is this? An original, or a BS? For a "race ported" original those would be sub standard numbers for sure. Also an original on a 451 is a LOT of head and I'd guess wants a LOT of RPM to be happy. Been there done that as my first B1 engine was a 451. Also you are not running anywhere near almost 800hp worth of MPH, you are likely close to 10MPH off for that HP and weight. So something is quite a bit off in the combo and numbers