Rear End woes....Help Please

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Mar 31, 2005 | 01:58 AM

superman64011

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Tuned

Joined: Feb 2004

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Rear End woes....Help Please

I have a 55 Ford F100. What kind of Diff do you run in yours???? I put a 4.11 Posi Track from MAE RACING in mine. When I am going down the Hwy around 60(not sure because trans cable is not right) it seems I am doing around 6.5K RPM with a 460/C6 combo. No overdrive on trans. I know that is way too high RPMs and it also makes my temp gauge go way up. I still have the old center I think it is 3.0 Gears..39x13 gears...If the 4.11 is way to high will the 3.0 gears interchange with the MAE posi? Thanks for your help

Patrick

Last edited by superman64011; Mar 31, 2005 at 02:10 AM.

Mar 31, 2005 | 06:58 AM

GreatNorthWoods

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From: Littleton, New Hampshire

Patrick,

A 4:11 gear is too high for highway cruising with a 460 unless you use it with an AOD. Large displacment engines do not like high RPM and are better performers in the low and mid range RPM band. The 460 would be much more comfortable with a 3:00 to 3:50 gear. I can't answer your question about the interchange.

Vern

Mar 31, 2005 | 07:17 AM

holland501

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From: houston

6,500 RPM is way too high. 4:11 gears should be running about half that at highway speed. Still on the high side if you do a lot of highway driving but that isn't why you got 4:11s in the first place, is it. First thing is get someone with a working speedo to act as a pace car so you have a constant speed. Also, and I know this may sound dumb, but are you sure the tach is hooked up correctly. Most have switches in the back that indicate 4-6-8cly. If it's on the wrong clyinder position, it could explain the high RPM reading. I've had friends play worse jokes on me. Good luck.

Mar 31, 2005 | 09:42 AM

superman64011

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Tuned

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Well I made sure my Tac was hooked up right......But it was on 4 cyl instead of 8....

He he he....Someone mentioned it to me at work but I forgot to check a while back........thanks holland

What is about safe Max RPMs out of a 460?

And still what Ratio do you fellas run?

Thanks Patrick

Mar 31, 2005 | 10:01 AM

Randy Jack

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Joined: Jun 2004

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From: Riverside, So Cal

Super -

I run a 351C, not a 460, but I have a 3:50 (posi) rear end. I have P295/50R15 (27" tall) rear tires and do around 3200 rpm at 70 mph.

This is a cool little website that lets you calculate what your rpm should be given tire size, tranny ratios and rear end ratio. Check it out.

http://www.car-videos.com/tools/speedrpm.asp

Mar 31, 2005 | 10:16 AM

51ford fan

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Joined: Apr 2004

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From: Seattle WA.

If you like the 4:11 and want to keep it, I would look at a Gear Vendors Overdrive unit. I know they are pricey but that's about the only way you can have your cake and eat it to.

Rod

Mar 31, 2005 | 10:40 AM

B/B ford

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From: Riverside CA..

I'm running a 280H cam in mine and it reaches peak torque at 3900 rpm (533.6)

peak H.P. at 4800 rp, (440) I,m running 3.0 gears but haven't highwat tested it yet.

They ran mine up to 5300 on the dyno but, said 5000 would be a good place to red-line it.

Wayne