this is one thing that has always confused me, could someone explain to me what side of the bore is the thrust side, maybe a detailed photo or diagram, I just picked up a 70 340 block and going to have it sonic tested, but would like to have a little more knowlege of this procedure.

Looking at the front of the block ; the major thrust side would be the 9 o'clock position of the cylinder on both banks.

The minor thrust would be at 3 o'clock.

The thicker the major thrust...the better the structural integrity


Ron

or to put it a different way looking from the front it's the left side of the bores. so on the passenger bank it's towards the outside of the block and on the drivers bank it's towards the inside

thanks guy's,that helps and I just wrote it down and adding this to my note's

Or, you can think of it as the side of the cylinder the connecting rod is pointing at on the power stroke.

R.

The attached sketch shows what causes it.

- The highest thrust occurs on the power stroke, with the piston moving down
- Since the engine rotates clockwise, the connecting rod is angled toward the left side of the piston
- The piston force is reacted by the connecting rod against the piston with the angle to the left

The side with all the cracks