The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Best way to get better gas mileage out of my 454 1961 K20

Brad54 · 08-12-2017, 07:33 PM

Manual trans with overdrive. The MY6 4spd OD has .72:1 OD.
A 5-speed would get you there too.
If it's got the original diffs in it, there's not much you can do for the rear, but the front is a Dana 44, and any gear ratio you could want is available. Swap the rear axle for something that has a decent selection of gears available, and you can then swap 3.42, 3.30 or something like that into it.
If you want to swap to a small block, you'd make the truck lighter, and a 290hp crate engine is a real good, affordable way to go.

08-12-2017, 07:33 PM	#11
Brad54 Registered User Join Date: Aug 2006 Location: Athens, Georgia Posts: 1,456	Re: Best way to get better gas mileage out of my 454 1961 K20 Manual trans with overdrive. The MY6 4spd OD has .72:1 OD. A 5-speed would get you there too. If it's got the original diffs in it, there's not much you can do for the rear, but the front is a Dana 44, and any gear ratio you could want is available. Swap the rear axle for something that has a decent selection of gears available, and you can then swap 3.42, 3.30 or something like that into it. If you want to swap to a small block, you'd make the truck lighter, and a 290hp crate engine is a real good, affordable way to go. __________________ '61 Suburban daily driver: off the road due to 180-pound 8-pt buck! '62 K-10 long-step project '61 C30 Camper, aka "Valdez" There's no cool like Old School