340 Tach Drve Electronic Distributor Question.....

That looks to be a marine application distributor, the housing looks to be cast steel. I run a Direct Connection tach drive dist. in my race car. It has an aluminum housing & looks identical to yours. I have owned mine for 25 years. I don't use a mech. tach anymore though, its easier to just run wires instead of the cable, plus the cable requires maintenace to keep the tach needle steady. Its a good piece.