I just reread some of your post 'cause I had missed where you mentioned a spare dizzy.
First check for side play in the dizzy. As long as you have one that is OK, next start testing.
Do the easy stuff first. Taking the guts out is time consuming so go collect data first - it'll be more fun too.
Check to see if that 6 BTDC was with the vacuum advance hose plugged or not. Good chance if you were real new to things then, it might not have been. In that case the engine was seeing 6 plus the vac advance unless you have the vacuum advance hooked to the carb's 'ported vacuum' or if there is little engine vac at idle.
In your notebook, record the rpm and the timing. Do this with vac advance hooked up, and with the vacuum hose plugged.
Second, with the vacuum hose plugged, measure the full timing advance. You can either do this by taking it to the rpm it stops advancing, or use 2500 - 3000 rpm. The former is more complete info (but scarier to do) and the latter is what the Mopar Performance and many others use as a reference point. Most small block distributors will be fully in somewheres in this rpm range anyway.
You will need either timing tape on the damper (cheap!) or a timing light that can be adjusted (called dial back). With a stock damper, I like the MP timing tape 'cause it has white marks on black background. For timing lights, I've been most happy with the digital one (arcus brand?) I bought through Northern tool. It has dial back and rpm readout. Makes it easy to measure a whole bunch of points so I can draw a plot of the whole timing curve.
When you take the distributor apart, the advance slots are stamped with the number of degrees. So until you mess with it, that (divided by 2) will be the degrees of mechanical advance. Your advance plus initial should equal the max measured.
Tune on the track or the dyno for max mph, then you'll know if any changes need to be made in the amount of advance (slots). Once you have the amount of advance done, and therefore idle and total, then play with springs and vac canisters as you like.
Oh, Whats this about and Orange Box AND and MSD6? With any MSD 6, the Chrysler ECU should be strictly for back up.
Wires. Since you're using the stock style high voltage wires, when these get to the end of their life, get the best you can afford. I've found the Taylor-Vortex caps are really heavy and well made, and their wires are pretty good but not so heavy. MSD's wires are also pretty good and seem to be slightly more heat resistant.
So will you pick up a 1/10? I think it depends a lot on the current condition of your ignition and most of all the maximum advance. On my current motor, we found 2-4 degrees less than 32 really hurt horsepower from 3500-6000. In fact it was putting the peak hp down at 5200 instead of over 5600. Remember HP gains are more visible in the mph than the et so for testing, you want to record both.
