1987 Ford Econoline Starter stays Engaged

I have a 1987 Ford Econoline E350 CUTAWAY, 7.5L V8 OHV 16V
When starting the truck the starter stays engaged and spins.
I have replaced the following parts on the truck:
1. replaced the starter' selanoid
2. replaced the ignition
Any suggestions on what the problem maybe and how to stop the starter from being hung up.
Thank You!

When you say you replaced the ignition, are you referring to the cylinder or the whole switch? The switch would only be an issue, if the "spring back" feature wasn't working on it. When cranking, key should naturally want to return to On position.
Also, the issue is not the starter itself, because on your vehicle, the starter motor & starter solenoid are separate. Starter, the part you replaced, is just the motor. All it does is spin. The solenoid is what controls the power from the battery & ignition switch to power the starter motor.

***UPDATE
Sorry I misread your post. I see now that you did replace the solenoid (maybe your spelling threw me off. IDK ) and not the starter motor, which I originally interpreted.

So my original question still applies, ignition switch or cylinder? Also, is the cylinder binding at all when turning? Is it bouncing back after cranking?