[RustyPile]

Look closer.. The starter isn't bolted to the block.. It's bolted to the bellhousing.. In the very beginning, Chevrolet designed the starter to mount to the bellhousing.. In 1955, when the first V8 was introduced, this mounting technique was continued for several more years. Judging from the picture, the starter you have is the early design high torque model.. Identified by its overall length.. The field windings are larger and require a longer starter main housing, identified by the copper extension between the solenoid and the winding terminal. I have this same starter on my 454 and it easily cranks the engine.

If the block is drilled for it, you can upgrade to a more modern starter but you may need to grind the bellhousing in that area to gain clearance.