An update on this, a bit late as I've been running electronic now since last August....
I did find and fit a full Bosch system from a CF van at a reasonable price.
The advance 'curve' is not ideal...I say curve, but in reality it is basically a straight line from 0 deg to the design maximum at about 3200 to 3500 rpm. The design maximum of a 8.5:1 2300 slant 4 is 36 deg plus 6 deg vacuum, totalling 42 degrees. A 9.25:1 2300 (HPF) is 32 degrees plus 6 degrees vacuum. The CF is 42 degrees and 6 degrees vacuum a grand total of 48 degrees...... A full 10 degrees more than a mildly tuned engine.
I didn't alter the advance curve of the Bosch and found that running it on the standard static setting of 9 deg BTDC it would pull OK to about 2500 rpm but start to loose power and stop revving at about 4800 rpm. Pulling the static timing back to 3 - 4 degrees BTDC cured the top end drop off and it revved far better than it ever did on the Delco 300. It pulled just as well as it did before from 1000 rpm to 2000 rpm but was a lot smoother and more powerful from 2500 to 4500 rpm.
The only problem is that it has difficulty in ticking over smoothly and doesn't start just as easily because it doesn't have enough advance at cranking and tick over speed.
To cure the starting and lower rev range problems I intend to strip the distributor and see if I can restrict the mechanical advance to about 32 degrees which will allow about 9 to 10 degrees static advance and add a bit more advance in the mid range, which should in turn further aide torque. A fellow enthusiast with a Bosch distributor has bent the limiting tabs in a bit but I'm not sure if that is really how I want to proceed. Yes, the advance will be limited but at a lower rev range than i would like.
I've decided on 32 degrees instead of the 38 degrees of the standard engine because I intend to add a Blydenstien big valve head, a VF2 camshaft and a pair of 48 Dellortos which I just happen to have sitting in my garage
. The DTV recommendation for the maximum mechanical advance on a tuned engine is 32 degrees.
So to conclude, the Bosch distributor from a CF is a good upgrade but you do need to sort out the advance by either getting it professionally altered or adding some sort of advance limiting on a DIY basis.