Oh dear Glenn,
Your post was discussed in detail at the Elstead Mill this lunchtime! Sorry if the flow of information was rather slow to start, but sometimes I just skip through and other times I have time to spare and can contribute more fully. Regarding your queries, I didn't have much to say because,
1, I have never taken out an Ace gearbox without removing the engine as well, so can't really comment. Mine is an Ace Bristol which is probably different anyway. There are lots of hands-on members who I would speak to, starting with the registrar.
2, I run Lucas distributor and points, but with an external condenser which appears to work well. I bought a couple of these condensers from a chap at Silverstone a few years back and would have to search through a mountain of paperwork to find a name and address.
3, The position and tension of the spring is vital. I would first check the camber and if possible the corner weights to see if it is sitting correctly. If that is all OK, then it must be body work or the wheels and tyres. I have a wheel with a slightly different offset which was just OK on one side but not the other. It is easy to swap the wheels over and see if the problem follows the wheel.
Thinking about funny things, we had an Ace come into the workshop once with a peculiar steering problem. Driving forward it wanted to dart to the right or left and didn't want to track straight. The camber and toe in was OK and all the components had worked fine previously, so we really scratched our heads. We then noticed it was 100% better going backwards, and it started to dawn on us that for come reason the caster was the wrong way round. It turned out that the owner had re-assembled his suspension with the left upright on the right side and vice versa. We swapped them over and bingo, it was perfect. Sometimes you need several cups of tea and a long think to work out what is actually going on.
Good luck with your project, and we must try harder in future to be helpful.
All the best, Andy.
PS Wasn't today fabulous! I went to the ACOC lunch at Elstead.in my Mk IV. We had a great turnout with a CRS, a Greyhound, an Ace Bristol, my Mk IV and Tony's beautiful Osca. On the way there and back about half the cars on the road seemed to be classics taking advantage of the early Spring sunshine. It felt great to be alive!