I've got a Big Mig Norvel .049 and have 2 (had 3) .061 Wasps. The Norvel is probably a better quality engine, but as you know they ain't making em anymore. Breakin time takes a bit and mine gets a little cranky from time to time, probably just the fact its an .049.
As for the Wasps, love them! I know its not a lot of difference in size, but there is a CONSIDERABLE difference in power in an .049 and an .061. Have 2 on a 44" wing plane right now and they pull with AUTHORITY! Flying on 45' lines it turns about 4 second laps, somewhere around 50 mph. With an APC 6X2 one engine will fly the plane.
Couple of issues with the wasps. You have to lock the throttle open. I stuck a paperclip in the linkage and wrapped it around the cylinder. Works and is easy. More importantly, the venturi is held on with 2 screws, one on each side. I lost them on my first engine with an unbalanced prop, they vibrated loose. With the 2 new ones, I loosened a 1/4 turn, put a drop of CA on them and tightened back, no issues to date.