AHA!, Autocross
Now we know why the 3.08s
Are you running mostly in first? cuz that's got to be hard on the mainshaft.
2.66 First x 3.08 rear gear =8.19 final-drive. You could get a similar ratio with
1.92Second x 4.30s out back=8.26
This would help get rid of the lowspeed jumpiness or at least move it down. The minimum roadspeed with 4.30s might be 5.6mph
As to your tune, I'll tell you a secret. The jumpiness is much diminished after you get the t-ports synced, with a minimum Idle-timing.By "retarding" the timing from what almost everybody says you need, the peak cylinder pressure comes later when the piston is a little further down the bore.And it is weaker. So it is transferred to the crank a little more softly.And so the jumpiness is smoothed out by the heavy flywheel.
I ran the 292/508/108 for a while, a long time ago. I ran it with just 14 to 16 degrees idle-timing. It was still a little jumpy with 3.55s and a 2.66 low. So I tried other ide-timings, but that 292 was not happy about that. So I bought a dash-mounted, dial-back, timing box, and started experimenting. Soon I found out, that I could retard the Idle-Timing to maybe 8* when it got jumpy, and that would smooth her out enough to drive a little slower. Then, when the parade was over, I could simply dial the advance back up.
But that cam and I just could not become friends, so one day I had opportunity to sell it, and I couldn't yank it out fast enough!