Donald Mitchell
1990 C1500 5.7L
I just guessing you have a c1500? I go to GM parts giant and look up the part number, then go searchng for somebody who has it. This is the one for a 1500 Gm 15973980. https://www.gmpartsdirect.com/oem-parts/gm-passenger-side-engine-mount-bracket-15973980?c=az0It Says the frame mount fits 4.3 5.0 5.7 7.4 1988-91