Vintage McCulloch Supercharger VR57 possibly Chevrolet into a boat

Let me start by saying I'm not sure what engine this fits.   It definitely fits a VR57 or VR58 supercharger.   I have it clamped to my desk to show you how it might mount.   It has two vertical mounting bolt holes 1-7/8" on center spacing.   It also has a big mounting pad on the back, which means I think it bolts onto the timbers of a boat engine framework with a rubber engine mount.   You could machine off this tab if used for automotive install. The pulley is what makes me think Chevrolet of some type.   It has a CH 6.18 cast into it.   I think that means Chevrolet 6.18" diameter, which corresponds to the measurement using my ruler. Blower pulley, drive pulley and idler are all wide-V-belt.   Blower pulley mounts on to VR57 and VR58 blowers. Your guess is good as mine. This is an unsual setup you don't see every day.

• Country of Origin: United States
• Brand: Paxton
• Type: Pressure Relief Regulator Valve
• OE/OEM Part Number: Paxton McCulloch Supercharged Ford Thunderbird, Factory-Supercharged Thunderbird F-Code, Ford Y-Block 312
• Manufacturer Part Number: VS57 VS58 VR57 VR58 SN-60
• Vintage Part: Yes
• Universal Fitment: Yes
• Performance Part: Yes