I am planning on a 6" leaf spring lift on my sig truck this year and I have some questions.

After installation, do I need to lengthen my driveshafts? I've heard yes and no on this
Will my stock brake lines be long enough or do I need to extend them?
Will the ujoints bind because of the increased angle?
Should I get longer shackles to make the axles tilt thus decreasing the driveshaft angle?
Is it really necessary to get 4:56 gears in the axles if I already have 4:10s?

 

How big are your tires going to be. You should be fine with 4:10. Any thing bigger than 4:10s is going to use a LOT more gas.

 

With a 6" lift you'll probably be running 35s? Or 33s? Either way 4.56 is about right. With 33s that gives you a bit more getup over stock and its about the same with stock for 35s. 4.10s will barely cut it for 33s and for 35s you won't like it very much I don't think. And anything with 6" lift and 35s will use a lot more gas I'd think lol.

 

My brother has 33s on his 97 f250 psd 7.3l with 4:10 and has get up and go. A 460 has alot of power at 230hp and 390lbft. it should be fine with 4:10s. My 89 7.3 idi has 4:10 and 33s and has get up and go.

 

With 33s oh yea 4.10s will be perfectly fine. I personally want more get up and go (don't have a big block sadly ) so I will probably be going with 4.56s if I do 33s and 4.88s with 35s. But yes 4.10s are just dandy for 33s. Besides you'll likely break less with them than 4.56s lol

 

I'm going to run 37s. I'm currently running 32s (only a quarter inch shy of 33s) at stock height with more than enough room for flexing and suspension travel. Bear in mind I have an F350 with a solid front axle and leaf springs on all corners.

 

With 37's you'll probably want 4.56's.

 

Yep, don't fear the gear.

Only reason I haven't stepped up to new gears is because my 4.9 falls on its face above 3000 rpms.

 

7.3 PSD,I ran 38s w/ 4.10s for years, it was fine. Switched to 4.88s for towing.

 

I had 35" tires on a super duty with the V10 engine. I went from 3.73 to 4.30 and ended up installing 4.88 gearing to accommodate the large tires. You may want to look into gearing steeper than 4.56.