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GRADYS Performance · 12-04-2019, 01:01 PM

My 85 Suburban C20 454/400 turbo updated to a 4L80E netted about 25% improvement in Fuel mileage towing at highway speed of 65 MPH. Rpm went from 2750 to 1950 with 3.73 and 235/85/16 tires.

12-04-2019, 01:01 PM	#18
GRADYS Performance Registered User Join Date: Dec 2013 Location: Columbus, Oh Posts: 366	Re: 78 K20 towing with 454 My 85 Suburban C20 454/400 turbo updated to a 4L80E netted about 25% improvement in Fuel mileage towing at highway speed of 65 MPH. Rpm went from 2750 to 1950 with 3.73 and 235/85/16 tires.