no clue what it is out of but wouldnt a 750 holly make a small 305 run rich as shit cause it doesnt run rich after i got it tunned. i dont want to pull all that shit off it now. maybe if i want to put some new heads or something. not a huge deal if it is i can get a 350 4 bolt main for 20 bucks just dont want to have to rebuild it. thnx thought yea 305s are sloooow as shit.