Since someone asked, here is size and part number information for the crankshaft rubber front seal for late production MGA (other than Twin Cam), all MGB and some MG Midgets.

For MGA (other than Twin Cam) the BMC part number is 2A939
Size is: 1-9/16" ID x 2-21/64" OD x 3/8" Thick.
(2-5/16" OD when installed)

Alternate part numbers:

	OS5910
	SC-1189
ABC	71-550081
Ajusa	15016600
Altrom	2113141
Apax	S5910
Auswes	2A939
Bearings Inc	1540673
Beck-Arnley	037-071, 037-446, 038-0166, 052-0627, W10714
BMC	2A939; 12G791; 12G3016; 13H4061; 13H6516; 13H6517; 88G561; 6031164303; 61164304
British Leyland	880561
C-H	550081 (Chicago-Rawhide)
Carquest	66550
Corteco	082165B, 12010683B
County	CNA473 or NA473
CR	550081
Gaco	45894
Goetze	50-304013-00
ITM	15-04001
L&S Bearing	71-550081
Lazorlite	U49-8440
McCord	ES17666-1, ES17672-1
Moss Motors	120-000
NAPA	66550
National	1873, 3878
OEM	3878
Payen	3970, NA473, P3141
Repco	211-3141, NA473, P3141, P3184, PR5692
Rover	6031164303, 61164304
Sealed Power	N-550081
SKF Automotive	S550081, 1OS550081
STAustin-Western	2A939
Timken	1873
Topline	TCSMG3
Vera	49-01350, 65-01711
Victor	66550, 441-0370
Victoria British	5-834
Weston	WRT13
World Parts

Applications:
AUSTIN 1000-Series MK II 1300; 03/1967-04/1969
AUSTIN MINI; 1959-1984
AUSTIN PRINCESS 1800; 04/1976-09/1978
AUSTIN-HEALEY SPRITE; 01/1960-10/1971
MG, MGA, 1622cc (from (E)16GC/8263)-1962;
MG, MGB, 1962-1980;
MG, Midget, 1963(#37647)-1974;
Mini, 1959-1980;
MORRIS MINOR; 09/1964-12/1971
RILEY KESTREL; 03/1965-12/1969

Speedi-Sleeve 99156 for 1-9/16" shaft size on the crankshaft pulley hub.