ATI 917270 uses the steel shell (9.75 pounds) and ATI 917268 uses the aluminum shell (6.75 pounds). I would like to use the lighter one but I do not want to interfere with eliminating harmonics. I read on net that the steel version is better at eliminating harmonics. Is this true?

I making a 385 that may go to 7k rpm.

Thanks
Derek

 

I have the steel one and love it. The aluminum has less mass and therefore weighs less. Not really what you want from a drag racing stand point. Im sure others will give you their opinion on the version they have.

 

I've used the aluminum shell and the aluminum hub on my NHRA Stock Eliminator combinations running up to 7300 with no problems. After consulting with ATI, I decided to stay with steel components on my LT1 Super Stock combination that was regularly seeing RPM at 8000+.

c