I have no idea if your system is correct but it seems strange to have two relays for the starter, the solenoid is already serving the purpose of a relay, of course with having no experience myself on your vintage GMC I'm just offering some thoughts. As HRL suggested, any relay suited for the voltage and current will work.
Last edited by 78buckshot; 12/17/2018 12:37 PM.
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
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