1983 Mercruiser 3.7L 185 HP Performance?

[Searay87]

I'm looking to purchase a 1983 Sea Ray SRV 255 Sedan Bridge with twin Mercrusier 3.7L 185 HP engines. They were re-built in 2005 by the owner who also happens to own a marine engine reuild shop. A quick scan of the Mercuiser site and I can't find this engine listed as one of the i/o options. From what I find on-line it's a straight 4 GM product. I would really love to hear from you engine gurus out there on the performance of this engine. Thanks!