GALV,
Yes, progressive linkage allows you to run on one carb, and then and some point it will open the others. All of them will end up at wide open throttle at the same time because the linkage is designed to open the others quicker, since they had to start opening later.
Most 2x1 setups are run together, not progressive. However, I have seen it done sucessfully without any apparent lean out issues at the far end of the engine, based on how the plugs looked. There are no progressive linkage setups available for the 235 engine, as far as I know of. I made mine from scratch. A progressive setup for a dual quad V8 might be adaptable for a 2x1 setup, but I haven't personnally looked into this. Possibly the flathead Ford V8 guys might have something you could use also.
