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Chevyman350 · 06-17-2011, 06:40 AM

HC8 RPO 3.21 ratio gears....

Does anybody have info on what these came in?

Production numbers?

Standard on which trucks?

Where I could find some?

I want them for my 1987 R30 cummins conversion. I need a taller gear for the tire size I am running and expected cruse rpm.

I have a 3.73 Dana 70HD right now.

Thanks alot!

06-17-2011, 06:40 AM	#1
Chevyman350 Registered User Join Date: Dec 2009 Location: Madison, Wi Posts: 80	HC8 3.21 Gears For Dana 70hd or 14 Bolt? HC8 RPO 3.21 ratio gears.... Does anybody have info on what these came in? Production numbers? Standard on which trucks? Where I could find some? I want them for my 1987 R30 cummins conversion. I need a taller gear for the tire size I am running and expected cruse rpm. I have a 3.73 Dana 70HD right now. Thanks alot!