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capev86 · 03-12-2013, 11:32 PM

Gear Vendors sucks....costs tons of money plus all that custom fab work required and the o/d ratio isn't very good (that's why Copperhead was still turning 2500rpm at 60). these really belong under a motor home or in a vehicle that is always towing heavy loads where the extra power and gear splitting is most useful. otherwise just a modern overdrive trans and moderate rear axle will net you the best mpg. my dad's 87 burb c10 didn't really lose any mpg going from a 3.08 to 3.73 (soft gear made for a lot of shift hunting) and his current 99 burb c1500 350 w/ 3.42 rear gets 22mpg on the highway.

i see no reason to change when the original 307 in my 72 Burb C20 runs so beautifully (thanks to a Petronix kit and a Q-jet swap). but those modern LS engines are awesome and you can't beat fuel injection on cross country trips (carbs don't automatically adjust to altitude changes). i'd love to stick the 4" stroker crank from a z06 motor in a 5.3 for the best balance of pulling power and economy.

03-12-2013, 11:32 PM	#25
capev86 Registered User Join Date: May 2009 Location: Eliot, Maine Posts: 1,314	Re: 1972 Kid Carrier Project Gear Vendors sucks....costs tons of money plus all that custom fab work required and the o/d ratio isn't very good (that's why Copperhead was still turning 2500rpm at 60). these really belong under a motor home or in a vehicle that is always towing heavy loads where the extra power and gear splitting is most useful. otherwise just a modern overdrive trans and moderate rear axle will net you the best mpg. my dad's 87 burb c10 didn't really lose any mpg going from a 3.08 to 3.73 (soft gear made for a lot of shift hunting) and his current 99 burb c1500 350 w/ 3.42 rear gets 22mpg on the highway. i see no reason to change when the original 307 in my 72 Burb C20 runs so beautifully (thanks to a Petronix kit and a Q-jet swap). but those modern LS engines are awesome and you can't beat fuel injection on cross country trips (carbs don't automatically adjust to altitude changes). i'd love to stick the 4" stroker crank from a z06 motor in a 5.3 for the best balance of pulling power and economy.