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Chevyman350 · 06-18-2011, 03:04 PM

I understand that the cummins want 1500 - 1800 rpm for peak mileage.

I like to cruse interstate at 75 mph (Midwest is mostly 65 speed limit).

I will be using 225 70r 19.5" tires.

06-18-2011, 03:04 PM	#8
Chevyman350 Registered User Join Date: Dec 2009 Location: Madison, Wi Posts: 80	Re: HC8 3.21 Gears For Dana 70hd or 14 Bolt? I understand that the cummins want 1500 - 1800 rpm for peak mileage. I like to cruse interstate at 75 mph (Midwest is mostly 65 speed limit). I will be using 225 70r 19.5" tires.