B&M tensioner identification

I'm having a older B&M 144 rebuilt and going to use the standard tensioner that bolts to the snout. When purchasing this old blower, in the box was a second tensioner......ANYONE know what application this thing is for. I was told it was a block mount type used in marine applications and I also was told it mounts to stock chevy tensioner set ups????? Don't know if I can use but it sure is A LOT more heavy duty that the one that bolts to the snout.

Thanks guys

tqz

P.S. the second pic is the pulley I have to use for my set up.

Nobody here knows the application for that first b&m tensioner??

do u have the 6 rib set up?

TQZ, yes that pully mounts to the block on a Chevy where the stock Chevy tensioner mounts. I have the same set up on my 1993 Chevy truck. Also if you dont use the tensioner (first Pic) I would you consider selling it. Let me know.