The brake problem could be a stuck check valve or an internally separated vacuum line,among other things. The lack of power is very likely due to having the heat riser welded SHUT. I've seen 'em wired,propped or welded OPEN before,and that's pretty harmless,except for making the carb warm up slower and susceptible to freezing under certain driving conditions. Don't ask how I know this.
The added backpressure COULD burn valves,so it'd be a good idea to get it opened up very soon. If it's too screwed up to use,I think the parts (spring,rod,butterfly,and even bushings,etc.) are still available to replace it.
Speed
