Just throwing it out there... I have the timing chain cover off a Volvo penta 305 SBC due to a bad crank seal. While im in there I'm considering replacing the timing chain and camshaft. I was thinking of putting in a Comp Cams XM262H:

•RPM operating range 1300 - 5500
•Duration advertised Inlet 262°, Exh 268°
•Duration advertised @ .050" Inlet 218°, Exh 224°
•Valve lift with 1.5 rocker Inlet .462", Exh .477"
•Lobe separation angle 112°

Its an internally stock (non vortec, hydraulic flat tappet camed) 305 with a rochester Q-Jet 4 barrel, Edelbrock Alum Performer Intake, Pertronix Electronic Ignition conversion, and Hi-tec Marine Stainless Headers. Wondering if the cam would compliment theis setup. I know new lifters are needed... But wondering what else would have to be changed, like valve springs etc.

Mark,

What RPM do you want to run ?

The owners manual says recommended is 4200-4600. I've read older Volvo AQ drives are good for 5000. I'm thinking anything under 5000. The boat was running 4500 with a 21P prop and 50 mph last summer without the hi-Tec stainless manifolds (just put those on this winter )

The next step down may be better suited for your rpm range. Any clue what your stock cam is, lift and duration ? guessing 195/200 @ .050

Only stock info on the cam from the shop manual says: Cam lift height - intake, 0.263 in / exhaust, 0.269 in

multiply those numbers times1.5 and that is the lift at the valve.

Maybe one of these, the tech line may be more help, http://www.compcams.com/Company/CC/c...x?csid=83&sb=2
http://www.compcams.com/Company/CC/c...x?csid=98&sb=2

Would the springs have to be changed with the XM256H?

size the seat pressure to the cam profile, I would change them on any cam change,

What exactly are trying to accomplish?