help with measurement

[Anonymous]

did i measure my intake pattern on my new head correct for a 2 barrel adaptor. i got 3' bolt to bolt and 13/4 hole size. i cant find an adapor that says 3' what should it be its a 1969 ford 250. I am buying a new holley 500cfm is that to much fuel for my motor. I am putting a
CSC-264-10-SHS 264/264 214/214 .450/.450 .480/.480 .495/.495 110* 1400-5000, from mike. right now i have a 350cfm but no aftermarket cam

 

[mustang6]

Are you measuring the bolt holes across the head itself or across the OEM spacer that's bolted to the head? The bolt holes across the head should be either 2-3/4" or 3-5/8". A 1969 250 should have a 3-5/8" spread.