76maveric, you've been worn down by our nasty, evil performance is everything thoughts. Soon you will be cheating budgets like a real hot rodder!
I've checked the 2CG's before, and they are not the same bolt spacing, but they are close. There are two type of bolt spacing for the Aussie Stromberg 2-bbl. One type was run on the GM Holden 186S six cylinder and 253V8 , and the other one that was run on the 250 2v was a different bolt spacing.
The Rochester Productions 2CG is a great piece of equipment at a piece of junk-price. At Charlton Autos in Gore, my mate Woody would sell a fertilizer sack full for about $50. But I haven't figured out how to bolt 9 2CGcarbs on a 250....yet!
Filling and drilling a 250 2v manifold will allow you to fit a 2CG. Double nut the studs, then remove the studs. Just have a fitter TIG weld the four bolts, and then redrill to suit the 2CG bolt pattern, tap and die the hole, and place some new bolts in there. Nothing to it!