"Hi John,
For what I know,
"Hi John,
For what I know, the AQ165 and AQ170 have the same block (B30). The main differences are that the 165 and 170A have one type of cam and head, which are different from the ones installed on the AQ170 B & C. The latter two are higher compression engines.
The B30 block was installed on Volvo 164 cars in the 60s, so it is quite an old engine model. I believe there is no difference in the internal parts (pistons, rings, bearings, etc) between the automotive and marine blocks, so it would probably be cheaper to buy an automotive engine overhaul kit. However, the head gasket must be "marine", as it is in contact with salt water."