RE: CMB .67 nitro dual plug engine
Yeah, that baby ought to scoot! 40-60% would work in that engine as the twin plugs will allow you to use higher nitro. You just don't see those engines around much any more but I've seen twin plug engines as small as .45's using them. CMB must have seen some kind of performance gain for them to use that head but how much, I don't know. It sure seems to work in fuel drag cars though.