I just came over to I/O stuff from outboard drag racing, so my learning curve is at the bottom over here.

Can a 496 be used as a drop in replacement for a Gen IV 454 with Bravo I (I was told Gen IV, I do not know if that is accurate), it is a 1989.

Any other suggestions if a 496 will not work?

I am not looking for more speed, just reliability. I want to have my ducks in a row for replacement when this 454 goes.

Scott

Hey Scott,

Not sure what boat you have but I sold a Scarab 23 SCS to a buddy with older 454 and he did the swap to 496 HO. I think most of your problems will be with exhaust and fuel line return. Should be abale to be done.
Good luck with it

I think I can deal with the exhaust. I did not think about the fuel return, but I can deal with that also. Mostly concerned with engine mounts being in the proper location for engine to outdrive fit, and being able to use a Bravo 1 with a 496.

Scott

there is no fuel line return, on the early one's anyway. the exhaust is offset and you will need a lot more room in front of the engine in the engine compartment . corsa makes a fix for the exhaust if you are running silent choise. Make sure the fuel filter does not hit on the stringer. the mounts are in the same place. just did the same swap this past weekend . i would say the only problem you might have is the air cleaner will be into the backseat, hard. we had to move the seat ahead which ment moving the sun pad . it's a lot more work than you think to move the seat ahead. good luck Jeff

It should fit if youhave enough space in the engine bay.. I just did one... pic below.. It may be close to the rear seat, and be a bit of a squeeze getting into the hatch, and you may have to disconnect some accessories then remount them after the motor is in... You may also need a new wiring harness to the helm if you have the older style cannon plug with 3 large pins instead of the newer style with 2 large pins. If you have an older tachometer, you will need a signal converter, or buy a new tach.. I did not have a fuel return line, so that was not an issue. You may need some metric bolts depending on how complete the 496 is.. The engine mounts are in the same place, but I made sure that the drive was aligned properly after installing everything. If you have the new style 496 Merc riser manifold and a standard Bravo transom exhaust cutout, you may also need some angled/curved exhaust tail connectors. I just reused my CMI headers, so ther was no problem. However, I had to get creative with mounting the MEFI Controller and the fuse panel. I would also suggets buying a service manual... Mine helped a bit decoding the wiring harness etc.. It was pretty straightforward, compared to other engines I have toyed with..

Hope that helps... Good Luck..

I will stay with the carb'd 454.

Thanx for the replies.

Scott

You could rebuild your 454 with a 496 stroker crank, get a performance cam and likely make more horsepower for less money than putting in a late model 496.