I have a used ATI mandrel for sale. I had it on a LS chevy engine. This is a Big block chevy mandrel part # 916631, that ATI modifies to fit the Chevy LS engines. The LS engines crank bolt sticks out more than the big block chevy balancer bolt. This requires the Mandrel to be hollowed out some to allow the bolt to insert inside the mandrel sufficiently bolt it on. Then it is bolted on the balancer using the 3 bolts supplied in the regular way. Will fit either BBC or LS engines.
It is the standard 1" size shaft.
It has the standard 1/8" slot cut in the Mandrel shaft to allow use of a keyway to attach a pulley.
I installed this mandrel to use with an alternator, so I also included the 5" deep groove pulley and aluminum spacers used on my setup.
$100 shipped OBO.