Dale,
My '71 was originally set up with Hotchkis front and rear springs, Hotchkis/Bilstein shocks, Hotchkis front sway bar. It worked pretty well, but the rear dipped quite a bit on acceleration, and I didn't get the quite the drive off corners I thought I should. The CAT5 springs were quite a transformation - the rear dip was gone, the car really hooked off corners, and the overall feel was more stable and locked down. On the flip side, the ride was significantly harder on the street, but not enough that it bothered me.
The CAT5 springs use solid spherical bushings at the spring eyes, which eliminate twist along the long axis of the spring and thus in theory reduce leaf-to-leaf rubbing and binding. And they're very stiff in the front half of the spring, so the spring acts more like a control arm, doesn't wind up much at all, and has greater anti-squat effect. It all seemed to work very well for me, at least in that application.
As I said, on the 2nd gen I used the Bilsteins to begin with, and later switched to adjustable AFCOs sourced from Global West. The AFCOs were an improvement, but not huge. On my current '69, I use Detroit Speed double adjustables. I set them initially to the baseline that Kyle and Stacy gave me, and I've never had to move them more than one click from that baseline. That's one of the advantages of buying from a premium vendor like DSE - they've done almost all of the testing and experimentation I'd have to do myself.
Just my opinion, if it was me I'd go back to the Bilsteins for now, sort out what you want to do with the rear suspension, then work with a trusted vendor to see what shock package matches your combination and goals.
On the front end, the only thing I'd take a look at is more spindle height - even taller ball joints. The factory geometry is so far gone that even a 1/4 inch more can help a fair amount in stabilizing the roll center. One company that flies below the radar in terms of brand recognition, but really delivers on practical value is:
http://www.scandc.com. I used adjustable upper control arms and taller ball joints from them on my '71, to great effect. Mark, the owner, knows what he's doing. I'd give him a ring and let him know your current setup and goals; at the least, you'll be more informed after the call than before
Edit:
Oh, when it comes to trying a new track, I'd start with RMP. Beautifully constructed track, both more challenging and more rewarding than PIR, but still wide and safe. Near Olympia - probably less than 2 hours from you - and still plenty of amenities relatively close by. Biggest problem with ORP is that it's in the middle of nowhere. Nearest hotel is 8 miles away and only 10 rooms, for instance, and there's gas at the track, which is good because nearest station with premium is 30+ miles away!
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
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