And on top of that, bottom ends of SB Fords with the OEM cast steel cranks, bearing webs witout enough meat (except the Mexican or Aussie versions) leave something to be desired. Particularly with being overboosted. Now....if you were to use one of the new SVT blocks, and with a billet crank - that would be worth the effort. And, yes, a 6-71 is too much for a street driven small block of any brand.