C6 overdrive

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Jun 1, 2015 | 08:10 PM

doug51f1

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From: Athens, GA, USA

C6 overdrive

Anyone know where I can find an overdrive unit for a C6? I've got a 69 F250 with 390/C6. 8 mpg is tough to stomach.

Jun 1, 2015 | 08:12 PM

HIO Silver

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From: NorCal

Gear Vendors Overdrive:

https://www.gearvendors.com/f2wd3s.html

Jun 1, 2015 | 08:42 PM

doug51f1

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From: Athens, GA, USA

Thanks. I was hoping for something a little less expensive. I'll certainly go that route if nothing else turns up.

Jun 1, 2015 | 08:48 PM

HIO Silver

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From: NorCal

Quote:

Originally Posted by doug51f1

Thanks. I was hoping for something a little less expensive. I'll certainly go that route if nothing else turns up.

Well, you asked and I provided. I swapped a NP435 with a TKO... not cheap but I was recently rewarded with 17 MPG on a 60-mile test loop.

Alternatively, drop to a numerically lower gear like a 2.75 or 3.00. What rear gear ya running now?

Jun 1, 2015 | 08:51 PM

orich

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From: **** hole San Jose ca.

Keep the speed down to 50 mph and ya might get 10/11 mpg.

Most all new owners like putting the gas pedal down more then needed to get the truck rolling good..

Dual exh pipes can help keep the tires aired up. A good tune up all gets to some added points for better mpg.

Orich

Jun 1, 2015 | 11:05 PM

351Cleveland C4

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From: On the Edge of the Desert

High rearend ratio, 235/85 tires, headers and dual exhaust. You'll get the mid teens.

Jun 2, 2015 | 05:04 AM

jowilker

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Joined: Jun 1999

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From: Creedmoor, North Carolina

Sorry bub, but them ol 250s and MPGs don't comprenda. But should need the mpgs towed you have the truck to do it.

John

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Jun 3, 2015 | 07:06 AM

f100today

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From: DFW Texas

I think there is a e4od swap? But that's not cheap either. GV is probably your best bet. I've seen used ones out there.

Jun 3, 2015 | 07:51 PM

#10

F&M

Senior User

Joined: Apr 2010

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From: tulsa

My 66 M100 has a C6 and gear vendors.A 3:89 rear set should bring me in at 3:04 or so in the high hole.I'm hoping for high teens or 20MPG.I can't wait to give her a try.

Jun 3, 2015 | 11:12 PM

#11

orich

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Posts: 7,592

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From: **** hole San Jose ca.

Quote:

Originally Posted by F&M

My 66 M100 has a C6 and gear vendors.A 3:89 rear set should bring me in at 3:04 or so in the high hole.I'm hoping for high teens or 20MPG.I can't wait to give her a try.

Better get yea a vacuum gauge meter when using any kind of o/d for max mileage. If not you'll fall way short of your goal post.

Orich

Jun 4, 2015 | 12:06 AM

#12

351Cleveland C4

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From: On the Edge of the Desert

Quote:

Originally Posted by orich

Better get yea a vacuum gauge meter when using any kind of o/d for max mileage. If not you'll fall way short of your goal post.

Orich

For sure. My AOD turns my 4.11s into 2.75s. Big jump. If I'm easy I can cruise at around 15".

Jun 4, 2015 | 05:30 AM

#13

willowbilly3

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Joined: Jun 2003

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From: Black Hills of SD

Quote:

Originally Posted by HIO Silver

I think 3.55 is the longest legs you can get for a Dana 60, or that Ford put in anyway. With a 30-31 inch tall tire, 3.73s are a pretty good compromise. I've had several F250s with 390 and 3.73s and always ran around 12-13 mpg. In the old days of better gas I had several F250 4x4s with 360s that always got 12-13 on 4.10 gears (55 mph speed limit days)

Elcheapo overdrive- I had an old hillbilly neighbor in Alaska who put a T85 in his rear driveline on a mid 70s F350 4x4 crewcab.

Jun 8, 2015 | 03:53 AM

#14

Cracker289

Cargo Master

Joined: Jul 2003

Posts: 2,735

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From: Four Oaks, NC

Somebody makes an adapter kit to put a GM 700R4 behind a Ford FE, that might be the way to go if you're on a budget. Buy the adapter and find a used 700r4 locally to stick in there and you got OD.

Jun 8, 2015 | 09:00 AM

#15

TeachNlive4ever

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Joined: May 2015

Posts: 2,350

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From: Garland, Tx

I've looked into the Gear Vendor and the 700R4 adapter business. the bottom line is about the same. $3K!
There is an adapter for FE to 700R4, I forget who makes it(google it), but i recall it being $800. Rebuild trans.,starter, rebuilt drive shaft,Wire kit so the 700R4 will work, blah blah blah, $3K!!!
Next time i get rich, I'm rolling with gear vendor..