Holy Screaming 496 Batman!

Supersporter40 · April 9, 2009

Took the beast for the first highway drive last weekend and discovered it is turning over at 3000 RPM in sixth gear (manual tranny) going roughly 60-65MPH. Is it possible my tach is out somehow? It does seem to be revving quite high and even the big hills don't pull it down so it suggests it is accurate.

I would think 2000 rpm with 4:10 gears like my 01 would be more like it. Both trucks have the same gear ratio.

If the truck was made to run those high revs I am not too worried, sure seems high. It is wearing 33" BFG's too, hate to think what it would do with factory pizza cutters.

Thanks for the suggestions.

Ranger · April 9, 2009

Speedo might be off, or you're revving it too high in the wrong gear. I would think for 60-65 you'd be in 5th.

Supersporter40 · April 10, 2009

With a manual transmission I don't know how it could be in the wrong gear, it is up all by itself to the right. Speedo I guarantee is out by 10%

newbiewar · May 31, 2009

Took the beast for the first highway drive last weekend and discovered it is turning over at 3000 RPM in sixth gear (manual tranny) going roughly 60-65MPH. Is it possible my tach is out somehow? It does seem to be revving quite high and even the big hills don't pull it down so it suggests it is accurate.

I would think 2000 rpm with 4:10 gears like my 01 would be more like it. Both trucks have the same gear ratio.

If the truck was made to run those high revs I am not too worried, sure seems high. It is wearing 33" BFG's too, hate to think what it would do with factory pizza cutters.

Thanks for the suggestions.

I've got an 5 speed auto behind my 496, and at 65 i'm at about 2k rpms i think... 80 mph like 2400... my memory might be a little off, but i know accelorating from 65 to 80 i've got 2 more gears to down, 4th gear at 65 is about 3.2k and 3rd gear is like 4.5k i think

hockeypro1411 · May 31, 2009

Some bigger tires should take care of that for ya.

Supersporter40 · June 2, 2009

Some bigger tires should take care of that for ya.

Don't want bigger tires, it's for pulling the camper. Best thing we can figure is the needle on my tach is out of position. There is no way it idles at 1500rpm.

As to the scream at 65mph, I am thinking that is just the Magnaflow now that I am more used to it roaring all the time.

When it wore the 37's the tach said only 1800rpm at what I could best figure to be 65mph. I should have known right there.

It is doing great for pulling so far, burning half of what our 01/6.0L does to go the same distance and it could do it going much faster. Not that I need to, it is nice to be able to not get passed by the cyclists anymore.

My 6.0 sucks, I hope they aren't all like that!

Shaners · June 3, 2009

Yep your truck is not idling at 1500 RPM! You are off by 800-900 RPM. Was the gauge faceplate changed (white face gauges etc)? It is very easy to pull the bezel trim and get to the gauges to readjust the tach needle.

Supersporter40 · June 3, 2009

Yeah Shaners, that is exactly what it has. Thanks for the heads up, I will give it a tweak and be in buisness.

Cheers!

Shaners · June 3, 2009

Yeah Shaners, that is exactly what it has. Thanks for the heads up, I will give it a tweak and be in buisness.

Cheers!

Pop the bezel off and lower the tilt steering wheel. I believe there are 4 small bolts holding the cluster in place. Remove them and pull the cluster out of the dash. The clear plastic cover pops off.

Find out in here what the 8.1L should idle at (probably 600-700 RPM) and remove the needle gently. With the truck running press the needle back on the stem in its correct position then shut off the truck and reassemble.