Car acts dead after it gets hot...

agreed, starter relay: when its a no crank condition , jam a screwdriver between the threaded lug (BA) and the ignition switch input (SOL) and it will crank if the starter is not getting heat soak and opening internally. If it cranks when bypassed its the ignition switch. If no crank its the starter. Dont count out the Neutral safety switch from the trans but thats a longshot. Ha, reread it and it sounds like you already figured the issue out. Put a tet lamp on the SOL lug and attempt to start it, if the lamp glow, you know the ignition is getting 12V to that input.
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