My software tests were done using Performance Trends' Suspension Analyzer, which is the best suspension software I've run across. I also own Autoware's suspension geometry pro, which didnt impress me, and have tried WinGeo3 and SusProg3D. PT's program is definitely bug-free, offers full vehicle testing and many more outputs...did my homwork on this stuff too
With my own suspension, I really needed software that worked. Susp. Analyzer is also the most expensive, but worth the money if you need accurate data. I also use Quantum's 4-bubble gauge for double-checking camber/caster against the software.ANYWAY:) For my other suspension projects, I also have a stand with bare a-body front rails on it specifically for working on suspension combos. Without a car surrounding the parts, 3-axis measurments are easy to make and accurate. So here's the data I gathered on these spindles. Both tests were the same stock a-body suspension and kframe...I made my measurements with the A-spindles on, then only switched to the B-spindles and measured again. So, the only change was the spindle itself.
Re-Alignment required only a slight adjustment of the cams for the B-spindle.
All outputs here are in degrees. Tire was 24" diameter. You'll notice under dive, bumpsteer is decreased by quite a bit. This change alone should, in theory, reduce the oversteer tendency caused by excessive toe-in of the outside wheel on a lowered car. Caster gain drops a little, and camber gain goes up a little. Roll Center height is 1-1.5" higher, but none of the AutoX guys I spoke with had any problem with that. It wasn't raised enough to cause jacking, but even just an inch change helps somewhat with roll stiffness. I don't feel any of the changes here are enough to make the B-spindle the next big thing, but it's good to know that an easy to find part has no negative affects. I think these changes are very subtle, but I still remember 2 fellows saying their times improved in Solo events.
I have no proof of that though, so take that statement as you see fit.
Stock 73-up a-body suspension with 73-up a-body spindle. Ride height
for this test is 2"(at the wheel) lowered from mid-point of allowable
travel.
Dive ToeIn_deg Caster Camber RC_Ht
-2.500 .259 .088 -.178 7.970
-2.000 .126 1.205 .011 7.794
-1.500 .039 2.283 .072 7.503
-1.000 -.007 3.331 .028 7.146
-.500 -.019 4.356 -.106 6.752
.000 .000 5.362 -.320 6.336
+.500 .045 6.353 -.607 5.909
+1.000 .114 7.330 -.960 5.479
+1.500 .202 8.298 -1.377 5.051
+2.000 .307 9.256 -1.855 4.629
+2.500 .426 10.207 -2.391 4.216
'73-up A-body suspension with 73-up BJFMR spindle. Ride height for
this test was 2" lowered(at the wheel) from mid-point of allowable
travel.
Dive ToeIn_deg Caster Camber RC_Ht
-2.500 .389 .278 .871 9.631
-2.000 .238 1.298 .867 9.233
-1.500 .130 2.291 .766 8.793
-1.000 .057 3.260 .582 8.330
-.500 .015 4.211 .324 7.858
.000 .000 5.146 .000 7.384
+.500 .009 6.068 -.386 6.912
+1.000 .038 6.978 -.831 6.447
+1.500 .084 7.878 -1.332 5.991
+2.000 .144 8.770 -1.887 5.547
+2.500 .216 9.654 -2.496 5.116
Supposedly, the only difference from the '68-up body is that the frame rails and K-frame are 2" narrower on the early cars. I guess the '73-up LCA is different in construction too, but I think it's geometry is the same as the earlier piece.