Hi everyone!  I've got what I believe is a 1956 model 7U (serial 37449).  I've removed pony because teeth on the magneto let go & I figured I'd need to find them all plus take the opportunity to rebuild it.  Well, it's been welded at least twice & for the cost of rebuilding, I've opted for electric start conversion. 

My question is if I build plates to seal off the coolant passages that used to supply pony & diesel head, will that be bad for the diesel engine?  I can't tell from drawings if coolant flow through pony is in series or parallel to the main.  Any advice on blocking these off for electric start conversion is appreciated!

Won't be a problem. I have a direct start late model D2 that the hole in the bell housing is welded shut and the head has a plate bolted on. The battery tray bolts onto the bell housing where a pony motor would have been bolted on. The coolant still circulates through the head to the block weather there's a pony or not.