I service Generac automatic generators and had these in my used parts box, I see Radio Shack had a listing for them, I tried Summit Racing but nothing came up. Delcity, or a number of other on-line store have similar products. Just search for a 12 volt DPDT relay, the OMRON p/n I used has mounting ears, some don't.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy