What balancer

I use ATI, because they are top quality and rebuildable . I got mine years ago when my motor was externally balanced. When I built a new motor and switched to internal balance I just sent the balancer in to ATI and they rebuilt it and converted it to internal balancer (removed the counter weight) for ~ 40 bucks.

Edit: I also opted to have a Chevy pulley bolt pattern used so I have more options for pulleys....however, this may have been more trouble than it was worth.