If I wanted to run 36" tires on my daily driver, what would be the best gears for me to use in order to get the best gas milage?,keep the RPM's down ?,and still have great pulling ability? GMC 1/2ton,10 bolt. Does anyone know where I can find a chart? THANKS!

MIKE.S 84GMC,454

You have the T350 tranny right?
4.11 for mostly freeway and some city , or 4.56 for mostly city with some freeway.
But probably 4.11's would be best gas milage.

the 4.11's sound good,I was sure I wasn't goin to do the 4.56's since I'm on the road 99% of the time. But what kind of RPM'S do you think I might see with the 4.11's? No,sorry to say but I don't have a tac, and yes, I have a th350 trans. What about a 3.9? gear?

MIKE.S 84GMC,454

http://4lo.com has a good gear/tire chart, look at the "calc table".
From what you have described you want, and my personal experience, I know the 4.11 is perfect for you![img]/wwwthreads_images/icons/smile.gif[/img].
I had a 78 Chevy 400/400 with 4.11's and 36.5 grand prix tires, It was a good mix of low end torque and top end speed. the reason I mentioned the 4.56's is because I drove probably 75% city, 20% offroad with lots of sand dunes, and 5% freeway. So I always wanted a little more low end power and didn't care too much about top speed and if I was in the same situation again, I would go with the 4.56.
But like I said, you will be VERY happy with the 4.11 and I wouldn't go any taller (or numerically lower) like a 3.91 or 3.73[img]/wwwthreads_images/icons/frown.gif[/img]
by the way, do you know what your current gears are ???

3.08's stock. Let me add a question, I'm planning on swapping out my 10 bolts for some 1 ton axles this winter. I would guess that the ring&pinion are not the same from a 10 bolt to a 14bolt or dana60, right?

MIKE.S 84GMC,454

<font color=purple>Right.</font color=purple>

TEX

http://sites.netscape.net/gumboracing

It's weird that you asked that, cause I was just thinking of writing to you to say, with the 454 and 36" tires your 10 bolts are going to be the weak link, I wouldn't waste any money on the 10bolt you have, and upgrading to a 12 bolt is hardly any upgrade at all.
Alot of 14 bolt axles came with 4.11 gears (or 3.73's). Note a FF14 bolt from a 1ton would have 8 lugs, so you would need new wheels. Or you could find a 14 bolt SF from a 3/4 ton, alot of the 3/4tons from 88 and up had these with 6 lugs, so you can keep your wheels.
If you find a 6lug 14bolt SF with 4.11s, you can swap it yourself and end up not costing much more than the re-gear for the 10 bolt.
A D60 for the front would be sweet. But if you don't go four wheelin much, you could just re-gear your front end with 4.11's to match the rear, and it would be fine.
PS... certain axles have 4.10 gears, while others have 4.11's don't worry if you have one in the front and the other in the rear, they are close enough and wont cause any problems, (again I speak from experience, not theory)
You kind of mentioned towing, the 14 bolt would be a big upgrade for towing.
By the way 3.08's SUCK!!! with the 4.11's your going to have a big $#!t eating grin that you can't get rid of for about a month[img]/wwwthreads_images/icons/wink.gif[/img]

And there's nothin better than grinnin with sh!t in yur teeth! Yes, the 3.08's do suck. I have all that power with the new engine and no guts in the gears. The axles I'm looking at have 4.56's. I wonder if it would be easy to find someone that would swap there 4.11's for my 4.56's?

MIKE.S 84GMC,454

Put the axle with the 4.56 on and drive around (just don't put it in 4X4) try it, you may like it[img]/wwwthreads_images/icons/wink.gif[/img]
Or just get some 38"s instead of 36" OOH,,,, I like that idea[img]/wwwthreads_images/icons/wink.gif[/img]. Even if you do decide to swap for some 4.11s having the axle installed only makes it a little more uncomfortable to do.

So I put these 38's under my truck because I keep the 4.56's, then I gotta get another lift. I LOVE IT! But my WIFE, need I say more? I'm still trying to explain the axle upgrade. With 38's, what kind of lift MUST I have? Could I get away with 6" ? Here's another question, if I put 1 ton springs under my rig, should I expect a real hard ride? and what options do I have? I do want to pull a camper without draging my ass like I would with my 1/2 ton suspension but don't want to ride a rock. Wait a minute, am I being a picky-ass? And yes I know, pulling a camper with this dream truck might not be the smartest thing I've ever done but it sure will look good! Sorry, to many questions and more to come. Thanks Scooby!

MIKE.S 84GMC,454