So I'm looking for advise on my winter project. The boat is a 2001 single engine 28' stepped vee bottom bravo 1 believed to weigh somewhere around 6500 lbs loaded. It had a 502 mpi that I said I was going to leave stock . The plan is to install the 540 N/A for now and at some point add a Vortech/Procharger. I come from the car world and this will be my first attempt at a marine engine so let me know if something is out of place or not matched.

Stock GM block 4.5 x 4.25 +.005 decked flat top 9.3:1, .040 cometics
2200 cfm throttle body, Holley single plane 4500 efi manifold and Micro Squirt controller
AFR 315 cnc W/Inconel exhaust valves, scorpion rockers with girdle
Imco power flow's through transom no mufflers
Johnson or Morel lifters
I'm not 100% sure on the cam but thinking .640ish [email protected] intake and 249 exhaust
hoping for peak power around 5800-6000

Thanks for looking.

should be a nice engine, i think a crane 139651 cam would work great.

johnson lifters,the above cam and I'd change the exhaust manifolds to stainless marine gen 3's.

I'd go with a .051 gasket if the piston is out of the hole .005.

I hadn't seen that cam in my searching, do you think it needs that much exhaust duration for the blower or the small exhaust pipes?

On the head gaskets, the piston at full tilt was something like .018 which I'll have to double check but that would give a .022 quench before thermal expansion. I always thought the tighter the quench the more resistant it would be to detonation?

The exhaust and drive will definitely be upgraded before the blower goes on.

Thanks for the comments, keep them coming.

In a bbc marine build with steel rods, i personally would go with .040 as a minimum, .060 as a maximum for an NA build.

If the cam you posted, and the 651 were my only two choices, i would go with your cam out of the two, with a 112LSA. Jmo.

The 651 cam from crane is a 244/256 114 LSA 632/632 lift

I assume the heads were surfaced also, in prep for the desirable, in that app.mls gaskets?
Should be a runner , quadrouple check your comp ratio calculations would be curious what your finished chamber volume is on that one .

The cam and lifters haven't been ordered yet so they are still a blank sheet of paper..
The heads are box stock and Afr claims they are 121cc so if the surface checks out good for mls gaskets they won't be surfaced.

I can pass on some info on what my motors are...
547's...10.3.1 pistons..
CFE heads, completely reworked, new everything
isky solid roller 710 lift, 286/294 adv duration red ball lifters needless
4500 carb...deck height was zero
new comp cam rockers
think clambers were 118???
mls head gasket...

going take boat out for first run since rebuild boat sat morning

i am confused,is the piston .018 below the deck or above the deck.also on my cam,the 651 has been used in hundreds of 540s,i have used it in my own 540,s with great results but the max power will be closer to 6400 rpm.