Inliners International Forums General Discussion Blown and Injected Buick/ Pontiac Turbo on a 230 250

Not my specialty, but the NASCAR probably has the largest PVCR of the 4 390s, which is what you're going to need for high CFM flow as a draw-through. If this isn't big enough you're limited to really big main jets to get your A/F into a good place.
IMHO the smaller CFM will restrict boost but it won't shut off, just more vacuum @ WOT than the original Q-J.