dude everything in this post i wrong except the last sentence.
if youre happy with the way it runs at the mo just ride it and in the meantime do a lil research on building a nice 4mm with a modded trans, you cant slap a 4mm crank into stock stoke cyl motor, they have to ported specifically for a 4mm, the fact that your guy who is doing the porting and machine work that luckily lives half a mile away suggested that shit is ridiculous....
having said that, if your going to listen to what he tells you and then ask for help on here...whos advice are you going to roll with??
thought you said you wasnt interested in buying a new crank now youre talking about building a 4mm stock stroke shitfuck fail motor, you have to kick that builder to the curb and deal with a shop whos primary business is BANSHEES
there is a few here i think http://www.bansheehq.com/bansheehq-sponsors/