The front suspension is in top shape. No binding. Only the inherant stiffness in design of the pivot points. Shocks are 3/4" from bottoming out at full drop.
I do need to replace one of the bags up front that has a slight leak in it, so I just might up the size to a 7". I'm only running at 75psi in the front as it is, but I suspect a lower pressure in a larger bag would soften the ride.
I'm really on the fence about changing out the frontend. My '88 has the same frontend as the Gen I Lightning and they have surprised many people in the AutoCross scene. I've never raced the truck or any other vehicle, so I don't know what is good or not. I should look into seeing if there is a local AutoCross club in the area and give it a shot.
The SALA or SLA I was refering to is a short arm/long arm suspension. Ford changed from the twin I-beam setup to this in '97, but the Superduty trucks still use the twin I-beams. The beams are a solid design and take a lot of abuse.
A lot of people say to install a Mustang II suspension, but I feel they just aren't strong enough for a 4600 lbs truck. I don't like the idea of a suspension collapsing when you have to make a fast move to avoid something or hit some road debris. I would like to design and build a suspension that uses common and readily available parts. Maybe someday, I'll be able to build a truck from the ground up and do my own frame and suspension.
I do have a few chassis books, How To Make Your Car Handle by Fred Puhn, Chassis Engineering by Herb Adams and Engineered to Win by Carroll Smith. If I ever get serious about designing a suspension, I might look into the Susprog 3D program but it's in the $500 range. I used Solidworks to model all the componants of the '97 frontend and it works quite good, as I can measure the geometery through out the travel of the suspension.

 

The lightening is one of the best handling pickups I have ever seen run at an AX. You would not go wrong basing a design on that setup. The Jag front and rear suspension is another great choice if you don't want to design your own. The XJ front end weight is very close to the front end weight of our trucks (that Jag engine is a heavy beast!) and the geometry is excellent it was designed as a high speed sportscar in sedan clothing. I agree on the MII based design, even when beefed up the geometry is not that great. Art Morrison builds a good front suspension replacement and even offers it bagged.
That's a good library start. I do believe there are some AX events in your area, if not, there is an active club in the Buffalo area that runs at Niagara Falls/Lockport venues.

 

Are you refering to the '93-'95 Gen I or the '99-'04 Gen II. The suspension I modeled above is the same as the Gen II.

 

Must be the gen II I've seen run. Truck was definitely newer than 95.
I know it's just a concept modeling, but either the upper or lower A arm mounts should have some adjustability to adjust caster and camber.
Areas to watch in cycling the model: camber loss/gain, toe increase/decrease, bump steer, akerman vs wheelbase.

 

Ya, I didn't bother with the details like the slots on the mounts. In the program, it's easier to locate the bolts in a round hole than a slot. Next thing to do is model my frame and see if everything will fit. There is a drop spindle available for this setup, which will help with my lower ride height. A buddy of mine has an '01 Lightning with the drop spindles and I want to measure them up. He road races the Lightning and is really happy the way it handles.

 

Be sure to run the dropped spindles through your program to see how much the geometry changes, and also graph their effect on roll centers. Slots are not the ideal way to build in adjustment, they are a by guess and by luck adjustment, and can easily shift under load (there is a LOT of side load applied). You want something that is positive and linear i.e. eccentrics, threaded ball links, or shims.