mystery part

[TRIFARI@aol.com]

I was going through my parts drawer and I came upon Lucas 37584 regulator.
 It's a monolithic block about an 1.5" square with three wires--red, black
and yellow coming out the back.  Ceramic insert packaging suggests later
model cars.  The date stamp looks like 474.  Anyone have an idea what it's
for??  Thanks John Trifari  1955 Healey BN1/1980 MGB