Cost for labor on stroker build?

Should be same labor to build one as 340/360/318. As long as you have stroker kit with I-beam rods that doesn't require notching block. If you are a under 500 horsepower street motor you don't need H-beam rods.

Stock 340 stroke is 3.31"... 4" stroker is 4.00".

That's a difference of .69" total stroke up and down. So the rod journal is only half that amount outwards than a stock crank. So the rod journal is only .345" wider outwards. That's little less than 3/8". THAT'S IT

It's not rocket science.