[QUOTE=Irelands child]Cliff - thanks for the response. I have often and sucessfully run Dura Spark distributors in the past and with either the failure prone OEM module or the MSD box. I chose to go the all MSD way this time along with the small diameter version. As far as the pick up failures - these are the same pieces as the Dura Spark so quality parts from any NAPA will work. The cap and rotors are some vintage GM, I believe, which I haven't determined yet. I have MSD spares of all maintenance parts anyhow.
The MSD vacuum advance is limited to 10* so everything is centrifugal during acceleration, with that advance maintaining and following the vacuum signal during cruise mode. Both Frisco and Cobalt have suggested that I try full manifold vacuum, and since they are a couple of the more knowledgeable 'tuning' folks here, I'll give it a whirl - but final analysis will be which I feel is better for my use. As I said above, it isn't a race car, but I will give it a boot in the butt if tempted.
Sun distributor machines are collecting dust in hidden old timey garages. The last time I had personal access for one, I was wearing a soldier's uniform - 1965. This brings up the point of Ford distributors. They are fairly easy to set up on a Sun machine but first of all, there are a limited number of
known spring rates plus there are no interchangeable advance stops. To modify the OEM dist. spring rates, you have to bend a couple of posts. If you need to expand or limit total advance, you have to either enlarge (easy) of decrease (no so easy) a limiting slot in the advance plate - more reasons to go with an after market distributor. Then - there is the drive gear. The OEM cast iron gear
will not work with my steel roller camshaft - it needs to be either a steel (Ford for sure) or a bronze gear for other makes.
Kinda snug in there for a full size cap and adapter:

Thanks again, the later gear of5ltr dist is steal and will fit older dist.the pickup coil is different,just changed buds msd not easey.nice looking engine.good luck cliff