Mine was addicted to ether also. I put the largest batteries I could find in the battery boxes and used 2/0 battery cables along with rebuilding the starter. That helped alot. I eventually rebuilt the engine and had the head rebuilt due to leaky liner o-ring. Now, I use the preheater for 20 seconds and the 1650 starts right up. I do plug the block heater in when the weather dictates. 

I bought a 1650 @ 2004 mainly for nostalgic reasons because we had one on the farm when I was growing up. Didn't know what I was getting myself into as it was in really rough condition. Mr. Schwiebert gave me advice on this topic several years ago on Y/T. He is a great resource.