Simple. Put a vacum gauge on a port below the throttle plates. If it's high and it idles real good it's the lower Duration one.
If its the 284 it will sound like a popcorn machine thats quickly popping pop corn and may not idle well and the highest vacum reading will be about only 14-16 and both of these should have something that resembles a stock intake.
If its the 292 or the circle track cheeter. Man you'll have nothing below about 3000rpm then it will jump and pull real hard up from there and will not idle good (unless I set the carb up) and your highest vacum reading will be from 14 down to maybe 10 or 12 and these should have a single plane manifold (something you can put or slip your hand under by the throttle bores) .
Both of the 284 and the 292 or the Cheeter should have uptop at least a 750 and perferably an 850 doulble pumper or some sort of Dominator or 6-pac with at least a 2500 stall with 2 inch exhaust tubes.
The smaller of the cams should not have a 3500 stall. A 1800-2200 would be best with 1 7/8 exhaust tubes or some kinda 4 into 2 into 1 try-w-set-up.
Hope that helps-ya
