if you ever get the chance measure the clearance at the middle of the K-frame and let me know where your at.
Sorry it has taken me so long to post this up. With summer coming here in the northern hemisphere, I've been real busy outside with my house.
The measurement at the middle of my K frame is 5.5 inches. With 235/60x15 tires my lower ball joint and inner control arm pivot locations are both at 10.5 inches. With this set up and the resulting upper control arm angles, I am at a 5.687 inch front roll center location, which is good for a stock suspended car. 4 icnehs would be better though.
I've thought about switching my spindles over to the lighter, taller FJM style which will raise the roll center to 6.5 inches. While this does raise the roll center location, it also reduces the moment lever arm, which is a primary measurement that contributes to body roll. Reducing the length of this measurement helps reduce body roll which allows you to control the same rolling motion with lighter spring and sway bar rates. Since I'm putting in the biggest torsion bars available in, I'm holding off on the spindle switch until after I drive with the new torsion bars for a while.
Ideally a spindle the height of the FJM unit with a 2" drop in them would be the best set up for a stock style mopar suspension. This would allow your car to sit low to the ground without giving up the wheel travel of turning down your torsion bars while achieving a 4 to 4.25 inch roll center in the front and losing a few pounds of unsprung weight in the process. I've looked at the Fatman Fabrication spindles, which are exactly as described above, but they aren't the sturdiest looking thing, IMO. I'm sure they are decent for street rods that are fairly lightweight and they probably have logged tens if not hundreds of thousands of miles on them without incident. I'm just not impressed with them as they are a simple flat plate with the upper ball joint mount jutting out the side.
John, if your reading along, here is another business opportunity for XV; forged steel, lightweight, tall, 2" drop spindles for $300 a pair or the same thing in billet aluminum for $600 a pair. They'd sell like $1 beer at a chili cook off.