I ran 10-70’s stock springs at 7400’. This was with the SPI pipe and Diamond S can. Also ran Stock can. Ran a 48-44 .36 helix. Sled only stumbled one time in 150 mi. This was due to me not letting the pipe warm up after a stop. We had a stocker stumble and noticed the pipe was rubbing on the cross member. Once we got it to not rub, it never stumbled again.