bore is 3.025 stroke is 2.437 makes it a 286cc motor. mdb had some of the block work done sold it to julio as a kit but it took a lot of work to make everything spin... lots of internal block clearancing ...rod hit the cam had to modify the dipper...crank came out of a briggs flathead had to mod the bearing journals to fit the bearings shave the bob weights to clear cam and cylinder..mod the cam to clear the crank..grind a lot of weld to get the lifters to work again..etc etc...what I got was in no way ready to put together, got it all right now, should fire it up saturday