Rpm range

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Jan 25, 2009 | 10:31 AM

Ritechous_23

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Rpm range

I put a aftermarket tac in my 85f-250 and wondering the rpm range at 75mph.This tac I'm using has been in my firebird,trecel,and now my truck.I droped the tac on the ground and may have damaged it.My truck has the 4 bbl 460 with c-6 tranny with 4:10 gears and also a 4x4.When I driving my truck 75mph on I-44,my tac says 2500 rpms.Does anyone with a truck like mine run the same rpms?

Jan 25, 2009 | 04:31 PM

srercrcr

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Not even close. Should be around 3800.
At 75 mph the engine should be pretty much roaring.

Jan 25, 2009 | 05:45 PM

bashby

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From: Charles Town, W bygod Va

https://www.ford-trucks.com/calculat...php/p-mph_rpm/
Get your tire diamater at tirerack.com by looking up your size and looking at tire specs

Jan 25, 2009 | 08:01 PM

Freaksh0w

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From: East Tennessee

Definitely must have damaged your tach. It's off by a thousand+ RPM. Unless you are running some 44" mudders you didn't mention :-)

Jan 25, 2009 | 08:18 PM

Ritechous_23

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I cant here my engin.The axel code for my truck is 73 and trans code is k and the tires are LT235/85/R16

Jan 25, 2009 | 08:30 PM

86bigred

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From: patricia ab canada

sounds like you have 355 gears,my 460 4speed runs close to that rpm at the same speed , but mine is 355 or 350 gears, can't remember exactly. you have the same size tires i do to, are you sure the previous owner didn't change the diff gears.