Captainkirk's Duster project

Any spesial reason you use those old forgings? If we dont care about money i bet you free up some horses with a newer design piston....

The "crack" looks like a casting issue to mee...
You may fill it back up with soot to cover it, or take the dremel and try to dig into it a little?
Maybe even heat on it with a torch(?) To see if there is any oil in the crack that would boil