My 71 Superbee would do this very thing on occasion

Kept going thru starter relays

Replaced ignition switch

Car would start , starter would stay engaged

Key off , starter still engaged cranking over

Factory hood pins sure didn’t help getting to the battery


The reproduction positive battery cable going down to the starter
You have the main positive cable off the positive side of battery
Then wrapped next to that is the starter relay cable

Here , under the black wrapping , the two wire cables where rubbing against the factory cable bracket mounted on the frame

Dead short

The factory starter cable bracket had lost its rubber protection over the two prongs , and eventually rubbed thru the insulation protecting the positive cables creating a short that you couldn’t see from the front side until I removed the starter , then that positive cable , and started working myself backwards

Simple but very frustrating , especially at car shows