I'll second what Heck has said.
When I got my 122 (Weber dgv) it was pretty sluggish. I had enough of an intuitive feel from working a lot on old motorcycles to be confident that the engine was strong, just the carb and tuning needed attention. Get the valves set, timing right, points adjusted, then start on the carb. One of the initial biggest things with mine was the linkage on the carb- eliminate the slop and get it cleaned and operating right. It was an "Ah, now that's more like it" moment. Of course I had to spend a lot of time getting the jetting right after that. I think a lot of webers were slapped on to 122s when the SUs got sloppy straight out of the box with some generic 'recommended' jetting. I've got an A/F meter on my 122, so I know I've got the weber jetted pretty darn well and it ain't jetted nothin' like it was originally!