Johnson manufactures two versions of these flexible impeller pumps to provide raw water cooling for Chevy large and small block engines.
The "350" small block version is the F5B-9 pump (#10-24228-1).
The "454" big block version is the F6B-9 (#10-24805-1).

Chevy engines are commonly used by Volvo, Indmar, Pleasurecraft, Marine Power and many others.

This pump is designed for direct installation on the engine crankshaft pulley or harmonic balancer.
Crankshaft/Harmonic balancer mount pumps are designed for high-speed operation (up to 5000 rpm), and are fitted with a drive flange which is bolted directly to the crankshaft pulley.
This eliminates mounting brackets, belts and pulleys.
Since these pumps are only supported by the ball bearings, they must be prevented from rotating by means of a torque arm attached between a (threaded) fastening point on the pump body and a suitable point on the engine to prevent the pump housing from turning and damaging or disconnecting the inlet and outlet hoses.

Ports are1-1/4" hose barb
Output varies with engine rpm see Specification Table
Maximum engine rpm is 5,000
CE marked
Instead of a neoprene impeller, this pump now uses the superior cross-linked MC97 impeller # 09-1027B-1 or 09-1027B-10 (0.064" larger along the vanes)