Just thought I would kick in a little help here for the issue of reversion in a small block 6.2L (377) Merc.
You really need the valve event timing and LSA to really see whether reversion on a cam will be aproblem, just duration and lift won't give you those perameters.
Also just as an engine builder, you might want to stay with longer tube exhaust as a small block needs all the torque it can make in a boat and long tube exhaust will always make more torque in a small block than shorties, unless its supercharged.
As for the cam in this merc engine, if its an efi motor you will probably find the LSA up around 115-117 degrees and that LSA with the moderate duration numbers listed here should not be a reversion issue at all.
Just some thoughts.

Regards,
Ray @ Raylar

It is as regular EFI Merc. Thanks for the comments Ray.

I would like to know what the LSA is.

A while ago I was playing with this on my Desktop Dyno. These are the cam specs based on the numbers from Crane. If in fact the stock 6.2 uses the Crane 104224, these numbers should be accurate and LSA is 112°.

I spoke with crane and they said they do make some cams for merc but didn't find the cam for this engine/hp configeration, there where at least 3 377's the blue merc racing scorpion, black scorpion (ski engine) and the mx 6.2 what I have found they all use different cams. Ray, thank you for your comments, somebody's gotta know what the specs of the plain mx 6.2 are?

This is where I got the info. You can try to pm bobl for more info as he has been in these 6.2's before. Good luck.

http://www.offshoreonly.com/forums/s...&highlight=6.2

Thank you very much , I see your in MO. I assume LOTO? I live outside KC and boat @ loto.

You're welcome! No, actually the Mississippi River (Alton Pool) north of St. Louis. We like it.