The Stovebolt Site Forums The Shop Area Engine Shop axle gear ratio

I installed a 454 w/TBI in place of a 350 w/carb. in my work truck recently and of course gas is now over $3.00 a gallon, I tow a 26'(8500lb)fifth wheel camper several times a year and the rear end has a 4.10 gear in it now. it's great for towing BUT for everyday driving it's killing me at the gas pump, Im thinking about changing the gear but I don't want to take away from it's towing capacity (much) I know it's not going to get great mileage with the big block but any helps... any ideas ?? "besides selling it"

You can use this site to help you figure gears.
http://www.drivetraindirect.com/t_gear_calculator.htm

For your towing I would not go any faster on the rear.

That leaves the question of how to get better mileage.
You may look in to an overdrive unit like the Gear Vendors, Ranger, or the Saturn. Probably in that order.
http://www.gearvendors.com/
http://www.high-impact.net/transmission_and_gear/rangeroverdrive.htm
http://72.20.96.178/commerce/ccc1105-overdrive-units.htm

They should solve your problem, and make towing even better.

Grigg

Grigg.
Thanks for the links
I thought about a gearvendors, Man... that would be awesome but it's pricey ($2500.00) have you or anyone ever used the ranger or saturn overdrive units ? I called a local shop and they recommended a 3.42 gear! That sounds crazy I think they were just "making the sell" I switched the 350 with the 454 because of lack of power and I think Id be right back to where I started from with the 3.42 gear "I should have put the Big block in the 51.. sold the 350.. and BOUGHT A DIESEL"
LOL !!

Your 48 is going to be awesome !!

You didn,t say what trans. you are running but what about a L80 auto o-drive from a early 90,s truck.

Sorry about that the trans is a 400T I looked into a 700R but I don't think it would handle the towing... but I'm not sure

Regardless of what you do, you're not going to get much better fuel economy. The money you spend on economy upgrades will never be paid for in savings at the pumps. Buy a beater light duty truck for daily driving and keep the tow rig a tow rig,
Just my 2 cents worth

good point about not saving money.
Assume the overdrive swap cost $1500, you get 12 mpg now, and with the overdrive you get 16, and fuel cost $3 a gallon.
It's late, and my brain is not working quite right. But I figure it takes 60,000 miles of driving with the OD installed to pay for the fuel savings. Someone check me on this please.

I just assumed you had a manual, as all real trucks have manual transmissions. If you did then I think that the Ranger OD is probably the best buy. You could switch to a manual?
If you did go with a manual you have overdrive transmission choices, like the expensive NV4500. Or with some work, and a flywheel, clutch and bellhousing from a big truck like a dump truck you could install a surplus cheap spicer 5 speed model 3053a from a deuce and a half with about .84 OD.
Or as mentioned before an automatic with an OD, but I know next to nothing about automatics. I do know that all un-computerized Allison's are direct drive. It was not until they were computer controlled that they were offered with OD, and the newest ones in a Chevy truck have two overdrive gears, high is about .64.

Grigg

'the trans is a 400T I looked into a 700R but I don't think it would handle the towing... but I'm not sure

If your TH400 is doing the job you have then I'm sure the 700R4 OD would do it equally well. I've done a lot of towing with mine w/o any problems whatsoever and 187K on it.

I have an '89 1-ton four-wheel-drive with a TBI 454 and a Turbo 400. I don't drive it much because the fuel economy is awful. Best I've ever done with a trailer behind it is 10. And that was rounding up.

The 700R4 or 4L60 are not heavy duty transmissions. I would not want to bet on them holding up with that trailer behind you. The 4L80 is tougher but expensive. Its the OD transmission based on the Turbo 400.

I keep thinking about a swap like this and since I don't use it much I would not save more than a few hundred a year if I could improve milleage by 50%. The economics don't add up. Since I have a more economical car I like to drive I just drive the truck less when gas goes up.

Thanks everone
I think your right Im going to leave it alone and keep it "a tow rig" I'll just have to get a economical car or truck for daily driving
Thanks

Todd