Help identifying Distributor

[RJChallenger]

Just picked up a box of Mopar stuff and in it was this dual point  distributor. It looks like a Mopar and uses a Standard product CH-304 rotor. It must be from the sixties judging by the oil lubrication hole. The only numbers I can see on the housing are I3P1
Any help identifying this distributor is much appreciated.

[anlauto]

Figure out the engine first by measuring shaft length, measured from mounting surface to lower end of distributor shaft.

Mopar LA engine – 3.875"
Mopar B engine – 3.5″
Mopar RB engine – 4″
–
Chrysler 331/354 Hemi – 4.25″
Chrysler 392 Hemi – 4.5″
–
Dodge 241/260/270 Hemi – 3.875"
Dodge 315/325 Hemi – 4.25″
Desoto 276/291 Hemi – 4.00″

Keep in mind 1970 440+6 340+6, Hemis all used Prestolite dual point distributors. You may have a winner there 

[RJChallenger]

No winner here. The shaft measures 4.25 inches in length. so it must be for a 331/354 hemi or 315/325 hemi .