I am buying an ATI damper for my internally balanced 406 project. I saw that they make them in steel and aluminum. When should you go for the lighter aluminum balancer? This motor should see 6500-6600 rpm.Thanks,
Doc

Doc,

I think the aluminum dampers are designed for serious racers that are trying to squeeze out every .001 in ET that they can. I would be concerned about the longevity of an aluminum damper on a car that sees many miles or lots of different driving conditions. A friend of mine races Super Stock and he had one on his Camaro. He kept breaking key ways on his crank. He attributed it to the fact that the aluminum expands at a different rate than the forged steel crank, possibly creating more clearance than needed for the interference fit. I will say that the balancer he was using wasn't a high-end piece like ATI usually makes. If it were me I would just use a good steel balancer. I run the ATI SFI damper on my BBC and it works great.

I went with an aluminub body on a steel hub, don't remember ATI's part number.