cant wait to see what you are looking at. Porting? other efficiencies?That chain is a work in progress. It was about .2 behind the other chains I sent out. Not bad but that's almost 20% slower. It will be better soon. I've got to get busy on some chains after I finish playing with the saw. Don't want to improve the chain and not know what the saw gained or not.
I remember on a 7900 Adam Clark removed the choke plate and used a piece of metal that would slide over the carb intake for a choke.