yes a 67 would be a step down. As for spool, a 71 would give better spool and same power. Apples to apples, the 2835's are DBB.

Heat dispersement is an argument I don't know about. I have not have engine bay temp problems as of yet (that I know of) but then again I coat any and all hot pipes...

The real issue is I can't bring myself to work on the car with the twins on.

Cheers,