So I am trying to figure out if keeping the IFS in my 91' F250HD with 7.5L 4x4 and buying a 6" lift kit for F250 is the way to go, or swapping the IFS out for an F350 front axle and buying a 6" kit for a F350 is the better alternative. Anyone done the swap? What was your reason? Any reason I should keep the IFS?

 

The TTB rides a lot better than a solid axle but obviously isn't as strong. No one can answer your question until you tell us what size tires you're going to run and what you're going to do with the truck.

 

well if its a tow rig/highway cruiser/mall crawler just for looks ect. keep the ttb and maybe just try and stiffin it up a bit with better axle shafts and junk. should be fine to run like 35's might wanna regear tho. now if your gonna be wheeling it hard i would do a sas mainkly because of stregth and ease of repairing stuff. you will get alot better flex for running ruts and rocks, to keep the rubber down and keep moving. the tradeoff is its alot stiffer on the road. but ive had a few jeeps and honestly the solid axle never bugged me with its stiffness. now my pregant gf hated the jeep tho it hurt her to ride in it

 

I say go straight axle, A good D60 will cost you $1000 and you still need the track bar and roll bars. It a straight bolt in deal otherwise. If you are looking for anylift look into a "reverse shackle kit" will give you 3-6" of lift and a much better ride when done. Down side is an RSK can only be done on the D60 axle, the ttb D50 will need drop brackets for the pivots with an RSK.

 

If he does all his driving on pavement and only needs 4x4 for snow and ice, does it really make sense to do a $2500 solid axle conversion?

I don't think so.

 

It's his call, no more pivot brushing going out, better ball joints, better axle all around. Plus if he wants a lift the RSK is the way to go. Way way better ride with the RSK.

 

For a stock unmodified truck, I don't think the D60 swap is nessecary, but for something lifted that much I think you'd be better off with the solid axle. It'll be stronger, plus it'll be much easier to get the front end alignment set up properly.

 

I am looking to tuck 37" tires and my driving will be mostly back and forth to work 8 mile drive, and lots of driving in the fields, tractor ruts and mud. with a little bit of Vermont woods driving, pines, logging trails, ledges, small river crossings, ect. Nothing to crazy but not just a mall crawler. If you ain't going to use it off road might as well be a Honda!

I also intend to still tow with it, camper and horse trailer.

I also already have an 89' F350 donor truck with the straight axle and all the extra parts. So my out of pocket expenses are already cut down. Also spare transfer case, motor, trans, ect.

My Girlfriend hates the way it rides now anyway, so even if it's stiffer no biggie!

 

If you already have the donor truck, then I say do the SAS no question.

And tell your girlfriend to quit whining, that's how a real truck is supposed to ride. It's not a Chevy.

 

Sounds like a SAS is the way to go, especially if you already have the axle.

 

I dumped the D50 TTB in my 84 F250 in favor of the D60 straight axle. I did this mainly because I plow snow with it, and tow some pretty heavy trailers; it was impossible to keep it from eating tires. Not to mention the TTB arms on the 3/4 ton D44 and D50 are prone to cracking and breaking right where the leaf spring u-bolts go. This is especially common with diesel and 460 powered plow trucks or anyone who is running big tires and abusing the truck hard off road. If you go with a D60 from a truck built between 85 and 91 it will be a kingpin version, these are MUCH STRONGER than balljoints. I say go for doing the swap if you already have a donor, you won't regret it... I sure don't!
John

 

I resent that statement, My Hondas get used hard off road. In places a Ford truck can't go.






ON EDIT:
SAS That truck.

 

I swapped a D44HD straight axle into my truck to replace the squatted out D50. I will say that it is rougher on the road, but it doesn't lunge every time you hit a bump. I don't know if all these trucks do that, but mine sure did. It also seems a lot tougher and doesn't eat up my tires like the D50 did. I have no regrets about the SAS.

 

LOL...let me rephrase that might as well be a KIA..

A friend suggested that I sell the straight axle and use that to buy the lift kit for my truck, Now I am thinking that i'm better off doing the swap and getting a lift kit for an F350. Thanks alot for all the help!

 

Solid axle HANDS DOWN.

I did the D60 swap into my 97 CCSB and added a RSK and SD springs
It ride BETTER than it ever did with the TTB and now I don't have to worry about it eating tires and needing constant alignments. The RSK i went with allows me to run 35" tires will all sorts of clearance.

I also just did another D60 swap w 3 HD leaf springs into my brothers 94 F350 2 weeks ago. He cannot believe the ride difference. It rides BETTER than it EVER did w TTB and leveling springs. On top of that, it turnes tighter and handles the plow better