Woke up this morning with the aftermath of a flu that caused evacuation from every hole. My attitude-bad. Like you had dc'd the subframe to get at the carb and it was time to put things back together, I was in no mood for a jigsaw puzzle thought up by Hitler's spawn.
Like you I had problems with the frame tabs hitting the subframe rails.
OK, I was pissed. Really pissed after dicking with it for 10 minutes. Hammer. First I loosened the lower subframe bolts a couple of turns, Next I got out the file out and filed off the square edges on both interfering edges and then got the big punch and hammer out of the box. Three good wacks on each frame tab, medium force seemed about right. Add a dab of oil and now and things will slide into place just like Hitler and Eva used to.
Seriously I agree with you. It is way easier to work around the carb if you pivot the subframe back and it should be "set up" so it comes apart and goes back together easily. The exhaust pipe bolt had been stripped by a PO so that gave a little problem but I rethreaded it. I used antiseize on the clamp and the muffler connection. Locktite everything brother and fixit right next time with the hammer.
Bill in Tomahawk, WI.