My mileage is ok at best. Im definatly thinking of swapping out my 4.10s for 3.55s. How much better mileage should I expect. I also heard 3.55s are better in the 1/4 mile. Is this true?

 

my 01 HO will hit 24MPG (hand calked) all day I have gotten 26 1 time but if I keep it at 62mph that seems to be the sweet spot

the 01 SO has a service body on it and gets 15 mpg at 10k gvw
both have 3.54s

 

I dunno what I get but im guessing around 16 with 4.10s

 

that is about the best I have got.

 

With a stock tire size you would enjoy the benefits of the 3.55. With the tire size you are at I would stick with the 4.10.

 

Yeah.. I have 35's with 3.55's and I hate it. At 2000 rmp's I'm around 82mph. I can't pull any kind of hill even empty @ 60-65 mph. My egt's climb pretty good. I'm wanting to go down to 4.10's in a bad way. Stay there!!! Don't do it!!

How fast you going at 2000 rpm's? 65?

 

Sea Bass is right...if your stock, or close to it.
I love my 3.55/35" combo....and I love 2000 rpm at 80 mph. But it does take HP to compensate for what amounts to a tall rear end.

I get high 16's for mileage around town...and can do 18 in a trip at 75 mph. You can't compare an auto to an HO, or any manual. It's apples & oranges.

I would think 35" tires on a 4.10 rear end might be just about right for the drag strip. I just did a 1.75 sec 60' yesterday (see signature).... so I can't complain about my set up .... but I still think I geared a little high??

I'm guessing 3000+ rpm at 110 mph would be close to perfect for qtr mile racing, if that helps you decide. I'm below that..... at 2800 rpm's.

RJ

 

Id stick with the 410s. I just did the swap from 355s to 410s and love the new found power turning the 35s. My mileage went up around town and stayed the same on the highway @ 75-85. Also while towing my egts have dropped a very noticeable amount.
mooseman

 

How much was the swap from 3.55s to 4.10s?

 

I cost me a little under 400.00 for everything. I have a buddy that manages a six states shop that does this sort of thing for a living so he was able to hook me up real well.
Average price with parts and labor is around 1000.00.
Mooseman

 

I just went from 3:55 to 4:10 also. With a 315 tire the truck slowed in the 1/4. Went from a 14.2 to a 14.6.

I have since corrected that with a set of injectors.
Check sig for updated ETs.

 

Your times got slower? I sure would have thought it would have been the other way around.

How did your speed compare at the end of the track?

 

Yup, lost the top end with the 4:10s. MPH was 94 when it went 14.6.