Sure your numbers are right i had a 25 outlaw with a496 ho and it went 70..

The increased weight of the BBC over the SBC is going to make the tail of the boat sit lower. That's going to put your tips closer to the water, and potentially start more issues for you. Make CERTAIN that your exhaust has 2 sets of flappers. External flappers, as well as internal butterfly flappers. You will also have to check the internal flappers from time to time to make sure they are intact.

Why are you so set against the efi? It is not that hard to tune. ESP for the power level you are looking for.

It sounds to me like he's dead set against it because of his "mechanics" don't know what to do with it. This sounds like it will be major drama in the long run. The 6.2s were blowing up due to reversion and it doesn't sound like the issue is being figured out so the 454 will do the same likely. Just make it dry exhaust and no worries. Lol

I'm still trying to figure out why you would take an efi engine and spend money to convert it to a carburated engine? You already have everything that you need there already. All you need is someone to tune it. Just because your "mechanic" can't figure it out, doesn't mean it's a good idea. I have some customers that would absolutely love to have EFI engines, and you are taking it off.
Eddie

Just spoke to my mechanic. I asked him do we know how reversion occurred. He said the 6.2 is notorious for this something to do with the cam design, he also inspected my exhaust and it's angles is to shallow flappers internally were not closing either. These all being addressed by new elbows and new flappers when new engine goes in

He also said go carburated because idle can be adjusted more easily to be increased bs the increased idle help prevent reversion/ efi won't adapt to cam he going with. He said to build the efi version with 475-490hp exceeds my budget for new injectors tuning etc, so carb is the best option

Good carb tuned properly is going to cost $1,000 fyi
Last 6.2's I did had well over 300 hours with no reversion issues at all

Not only can the EFI be tuned, but it has 10 times more tune-ability than a carb. Why do you think that no OEM, marine or automotive, builds a carb engine anymore. 99.9% of the engines we build are EFI. We can make a 1300+ hp engine idle at 700 rpm. We can certainly make a slightly hopped up 454 Mag idle with any cam you can stuff in it. Sounds like your "mechanic" either doesn't know how or doesn't want to mess with the EFI. I can absolutely assure you that the EFI on that Mag engine can be tuned to do whatever you want. The injectors are large enough to support about 650 hp. Honestly, the only additional money you would have to spend is to tune it, and that needs to be done with either induction system.

I'm just trying to make sure that you understand what you are doing. Personally, I think you are making a HuGE mistake by removing the EFI. Don't do what your "mechanic" wants you to do. Do what you want to do or what you think is best. Let me know if i can help in any way or answer any questions for you.
Eddie

The Crane 104224 camshaft ground for the Merc 6.2 is a relatively mild cam.Not the reaon for reversion. The riser angle and lack of anti reversion dam is the only issue here. Ask your mechanic to look inside the riser and see if it there's a dam inside.

I think this spec is for the Scorpion with a more lift & duration compared to the black 6.2 MPI that I have. What engine do you have?
From Merc Racing Service Manual 7:
Engine 377 CID (6.2L)
Lifter Type Roller Hydraulic
Rocker Arm Ratio 1.50 to 1
Valve Lift
Intake 0.510 (12.95)
Exhaust 0.530 (13.46)

Lobe lift +- 0.002 (0.051) I= 0.340 (8.636) E=0.3534 (8.9763)
Dur @ 0.050 I=222 E=230