Pretty much any one the right size will do, 541 from the junior scout, Harley ones etc, M7 I believe is an aftermarket replacement for the 45 cube. If you are having one rebuilt, may as well put the larger venturi in, but have run 741s without any problem.
A rebuilt schebler dlx is as good as a rebuilt linkert, altho they are harder to find in good rebuildable condition.
May have something here, give me a call.
860-482-9215.