RE: McCoy engines
Ole Duke did about everything he could to the 35 and still be able to call it the Fox 35.
Two bolt and three bolt back plates.
Hemi head
Silver
Gold
Fillets in the fins for longer head bolts.
Different style muffler attachment ears
etc
Was at the C/L field the other day and a OS 40 LA has a lot more power than a Fox 35. For what its worth.