I am looking at buying a 525sc that has about 200 hours on it but owner is keeping exhaust manifolds for another project. I have some other 454 manifolds from generation iv and V engines. Will they work on this motor? Mercury Marine is saying it wont because of different part numbers. Also have a standard bravo III ( not xr) in the boat and boat is 30 ft Mariah z302. Will this drive support the 525sc under normal driving? ( again mercury says 400 hp max on bravo III but it seems others have ran a lot more) Trying to decide weather to buy this or just build a 454 mpi like what was in the boat. Thanks so much.

Did the 525 have the Gil manifolds or headers? Either way, I would not run stock Merc cast iron manifolds/risers. Some take-off 496 (8.1L) manifolds/risers might work for you.

Do you have clearance under the hatch and at the engine compartment bulkhead for the blower?

I think Mariah built some of those 302's with a 500 EFI.

I think I have enough room but I will take some measurements to make sure. I think it came with Merc/gil manifolds. Looking for just a good replacement manifold.