Finally found the reason for the starter dragging.

[janschutz]

After I have driven my dark blue coupe, the starter would slowly turn but it would always start the 351W. I had replaced the starter (twice), solenoid, and thought I had checked all the connections.

Turns out my engine block ground strap was bad. It was corroded inside the insulation. That caused more resistance when hot. I replaced it and now there are not any starting issues.

 

[6t6red]

Good catch. I have a ground strap attached to the lower starter bolt and the frame rail to give the starter a good ground.

 

[tarafied1]

Good catch. I have a ground strap attached to the lower starter bolt and the frame rail to give the starter a good ground.

I added a ground to my starter as well. My battery is in the trunk so I have a long positive cable but only a short ground to the frame. The engine has two ground straps but I still had the occasional slow cranking when hot. Ever since I added a ground directly to the starter I have had no issues. :thum

 

[janschutz]

My battery is also in the trunk. Looks like I might need to add another ground to the starter.

 

[tarafied1]

can't hurt!