Well, That's kinda complicated. The Weber 32/36 progressive carburetor would be fantastic......if it was maybe a 40/42. But it's not. So it's really a hair too small for even a stock 225. A stock 170 and it would probably be a good match. There are plenty of other Webers, but IMO, a staged two barrel would just perform great.....but there are none really big enough. What I would do would be to run the Holley 2300 two barrel. Either the 350 for mild applications, or the 500 for more serious engines, such as turbos, higher compression, bigger cams, headers and such. You could also use a Carter BBD off a 318. That would be a good upgrade for a mild to moderate 225.