swapping a michigan motor unknown year must have been a 2 wheel dr smaller clutch both were equipped with air carb on mi motor has throttle cable on right California on left should I swap out manifold carb to the non California motor or try it as is California motor had blown head gaskets and bad cylinder walls Anybody with any experience or advice let me know thanks

To the best of your ability try to keep it as OEM on the Brat.  Only because I have a soft spot for the Brat and there are very few of them left as OEM.......  Hoping to get one.  Switching manifolds is fairly easy.

I have a 100% OEM barn find BRAT in my avatar. I had to change it out to a weber and magnaflow (among other things). The issue with the Ca emissions is that none of it can be purchased new. It creates vacuum leaks and robs performance (what little there is). Also, my 4 speed began having issues, and once again, no one has a 4 spd rebuild kit. (found out later the trans wasn't the issue)

 It literally started to become undrivable and I am not wanting to waste money buying parts from "Bob's" parts stash in Michigan or South Dakota that may or may not work.

 

BRAT's and many EA81's are modified to simply just keep them on the road. They have to evolve so to speak lol.

Got it all in and started and the freeze one freeze plug is missing on the drivers side head now my crankcase is full of water hope to be able to get it in without pulling the motor back out pull the rockers off waiting for the plug. Hope it don't rust up between now and than