7.3 diesel with 355 gears

Isn't that drop in mileage more a result of increased wind resistance which increases as the square of the velocity? If so, then it doesn't matter what gears you have. You'll need to add the same amount of power to overcome the resistance at 60 mph.

The only reason I mention this is due to an experiment that was forced upon me. I had belt sep in the 2 rear tires on one of my cars. I had to wait 4 days to get new tires and in that 4 days I was driving about 55 MPH everywhere (instead of my usual 9 over the speed limit lol). I noticed that average gas mileage took a 25% jump. Nothing else changed except velocity.

Just something to ponder.

My 7.3 is stock tune with a banks on it, runs exceptional just tired of 55 to 57mph to keep fuel mileage decent at 60mph I'm running 2000rpm and fuel milage drops so that has been my thinking on changing gears

djg wrote:
Has anyone had 355 gears with a 7.3 diesel was thinking about changing to them from 410's but want to know if it will be geared too low, also what rpm will 65mph, be at 410's at 1900 is about 56mph

Is your 7.3 stock or chipped at all? We pull a 12,000# 5er with a CTD with RV275 injectors and a small 50 HP chipfigure about 300 HP and 610 TQ.

Your total weight should not exceed about 14K we tow at about 20K.

Contrary to one of the replies here, if you're talking about a healthy 95 7.3 diesel, it's anemic in stock form. It should have just enough to haul a TC ok with higher gears, but it will be a bigger dog than it is now.
I'd keep the 4.10s unless you're looking for empty freeway driving manners to be better.
For future reference, don't believe any claims of towing 15klbs in overdrive with your truck, except maybe downhill.
Depends how much you want to sink into a truck compared to what its worth.

Lower numerical gears, ie going to 3.54 from 4.-0, is gearing higher.
I had the same situation with my 4.10 ‘99 Dodge dually.
I put in a Gear Vendors overdrive, so I still have my 4.10s for when I’m heavy but I hit the button and it’s 3.20. My 60 MPH RPM goes from a bit under 2000 down to a bit under 1500.

If your truck is 4WD the cost is similar. If you have 2WD and only have to change out the rear differential, it’s a lot cheaper to re-gear.

If you consider the overdrive, pay no attention to Gear Vendors wild claims of MPG improvements. It won’t make much difference at all, not will it ever pay for itself.
It does make the truck a lot more pleasant to drive. You’re not always wanting to shift up one more time like you do with 4.10 gears. That’s what you buy it for.

I think this is what I had in 2000 F250. Was pulling 15k trailers on overdrive just fine.
It was 4WD, so in case of need for low gear I could switch to LOW, but beside going into dirt, I don't recall need for it.
RPM comparison is straight math. Ask your grandson ;)