I've riden A GRISO. It's a hell of a machine... as long as you can get used to the feel of the torque of that Horizontal V-Twin (Remember, there's pushrods in there...)

I say wait to replace the primary first, then sell (If you have to... I know the feeling... there might be a "For Sale" sign in the future for my '76 750F once I get it all done)
#1 - Increased sale value
#2 - Decreased chance that the next guy to buy it will come back to you saying, "Hey, Buddy. This bbike ain't runnin' right..."
#3 - One last project to work on with her.