Short Shaft vs. Long Shaft

I am not aware of any advantage of the long shaft over the short, unless you have a NOS block, head gasket, head, etc. to use it in.

About every distributor I ever saw with a long shaft (and good distributor bushings) wobbled some in the head and if left alone wallowed out the hole and wore the distributor base. The rest had worn out bushings.
 
the short shaft acts in conjunction with the distributor shaft as a universal joint and takes up the wobble inherent in a shaft with such a long distance from the camshaft to the distributor. With a single long shaft, the wear from the wobble takes place in the distributor bushings or as mentioned above, on the head bore and distributor base. Some folks think they are looking at a long shaft when in reality they are looking at a short shaft that has rusted to the distributor shaft at the collar. The long shafts are another aftermarket "improvement" on Henry's design that will prove not to be so much of an improvement after all.
 
In rebuilding distributors have found the one piece shaft doesn't run true, wobble, causing point openings to vary. Suggest you use the two piece original set up.

Ron
 
The two piece shaft allows some movement and releaves pressure on the bushings. We run two piece shafts in all the Model A Times project cars.
 
Remember that head and block were machined separately, and that there isn't anything to register the head location more precisely than the studs anyway. Concentricity is unlikely, within available near-nothing clearance of a good shaft and bushings. Get new bushings and a 2-piece shaft set for that distributor!
 
IF you have the original ignition cable, it is easier to remove the distributor from the engine with the short shaft. Having the two piece shaft assy does eliminate the potential wobble of the distributor shaft/casing because of mis-alignment.
 
I had to file the joint between my 2 shafts to make them fit, which means that slop was minimized. I haven't thought it through if the single shaft could have it, but the drilling in the upper shaft allows dizzy oiling.
 
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