So if you look at RockAuto there is no 393 listed anymore for 510s. I only see 391 as a U-joint option... Oreilys website confirms that as well. If you look up 393 on Oreilys site, it doesnt list 510 as compatible, but there are other Datsuns that are. With some people saying theyve been using 393s and both websites saying 510s only use 391s, Im not sure what to believe.
Comparing the details on Oreilys site they are both greaseable. They are different sizes all together:
391
Lubricateable?: Yes
Lube Fitting Location: Regular Lube Fitting In Bearing
Bearing A Type: Round Grooved
Bearing A Diameter: 0.985" (25.0mm)
Length A**: 1.732" (44.0mm)
Bearing B Type: Round Grooved
Bearing B Diameter: 0.985" (25.0mm)
Length B**: 1.732" (44.0mm)
OE Series: Nissan & Subaru
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393
Lubricateable?: Yes
Lube Fitting Location: Regular Lube Fitting In Cross
Bearing A Type: Round Grooved
Bearing A Diameter: 1.103" (28.0mm)
Length A**: 2.205" (56.0mm)
Bearing B Type: Round Grooved
Bearing B Diameter: 1.103" (28.0mm)
Length B**: 2.205" (56.0mm)
OE Series: Nissan & Subaru
Hopefully I pickup the right ones. We shall see tomorow when I do my half-shafts. It would be nice if I could source an LSD locally and just do a CV conversion at the same time. Maybe that will be a Summertime project. I have some cash saved up, but not sure if LSD/CV is what I want to blow it on at this stage of the build.