How to tell the difference between distributors???

[DoubleDlover]

ok. So.. Your at a amc pacer swap meet... LOL And you find a dude with 2 mopar distributors on the table. You ask him. " is one of these for a 440?" He says, "yes one is. And one is a 383. But I forgot which is which." ok great. Now. How can I pick out the 440 one? Whats the easiest way to do that? r 

[A383Wing]

the shaft on the 440 dist will be longer than the 383 unit

[DoubleDlover]

hi. ok great. Does anyone have a measurement from where to where so I can use that to check? thanks r

[RallyeMike]

Approx 3-1/2 inches for the B engine and approx 4 inches for the RB engine.

[John_Kunkel]

Be careful when measuring, the LA distributor is 3 7/8"....close to the RB but rotates in the opposite direction.