GM (part stores) sell a different solenoid spring for $10 that cures heat soak issues without modifying the starter in any way. I do not have that part number, but a search may yield success.
Same starter, new solenoid ($13, just to be certain) and a $10 spring will cure it 95% of the time.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
