The 216-261 engines all use exactly the same distributor dimensions, the only differance being the composition of the gear when they changed to full pressure engines (they also changed camshaft composition).
The critical dimension is between the gear and the end of the oil pump drive. The distributor is a downthrust dist (cam pulls it inward) and the only way it is really restrained is rotationally by the clamp. If it fits in there and the oil pump gets driven, then it is ok. You can coat the gear with prussian blue, run the engine, and pull it out and make sure the cam runs in the middle. If you get oil pressure, you are ok.
I have a dual point conversion plate in my stock distributor. It works great. I got it for $10 NOS off e-bay, and it came with everything but points. It was made in the '50's and had the delco number for the points I need. It had a mounting bracket for mounting the condensor externally, too. Best $10 I ever spent.
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1950 Chevy pickup with '62 261, 4 speed.
[This message has been edited by 4onthefloor (edited 06-25-2003).]
