Wel I got some more info about this set-up. The regualtor seems to be sufficient and parts are available for it. Regulator
Here are some numbers off of the mixer:
1A-42227-A54
This is the tag on the mixer:
Marvel Schebler 3C-705 DTL 2408 G74.
It has 1 and 5/16" throttle bores
Funny thing is all my tractors have Marvel-Schebler carbs but I'm not finding anything on the web about the propane mixers.
I'll have to give the guys at propanecarbs.com a shout.
For $80.00 I might just take a chance and buy it. Pretty cheap if it works out.