christoner2002
Petty Officer 2nd Class
- Joined
- Jun 27, 2010
- Messages
- 139
First, I will give the stats of my Boat/Engine combo.
1997 Larson 206 SEi, with a 350 Mercruiser 1.62 ratio drive with a Turning Point 3 blade 21 pitch prop. Runs 55mph on a GPS in good water conditions. Boat is raw water cooled, never used in salt water
Engine was originally a 2bbl, which I swapped to a 4bbl when I bought the boat. I added a Edelbrock 1409 600cfm marine carb at that time
Heads are casting #14096217, 64 cc with what looks like push in style studs
It has the factory Roller cam setup in the boat currently. Manual shows the cam as #431-811658, with .394/.404 lift
Piston are a slight dish with 4 valve reliefs,
What I have is a set of freshened 12558062 Vortec heads, also 64cc.Stock springs and keepers, no upgrades. Pistons on the Vortec engine I got the heads from are the same style as my engine, slight dish, 4 valve reliefs.
Wanting to swap the Vortec heads on, and wondering if a cam swap would be the only way to see a real power increase? Or would the heads/intake be a nice addition alone?
I know I will need a new intake manifold. I have been looking at the Edelbrock Performer(idle-5000rpm) and the RPM Air Gap(1500-6500RPM)
My main questions are, would the original cam be ok, with the head upgrade? Or should I upgrade it? Would I need to change the rocker studs to screw in style, and would a RPM Air Gap be better then a performer Intake? Would like to see about 300hp out of the engine
Thanks for any input.
1997 Larson 206 SEi, with a 350 Mercruiser 1.62 ratio drive with a Turning Point 3 blade 21 pitch prop. Runs 55mph on a GPS in good water conditions. Boat is raw water cooled, never used in salt water
Engine was originally a 2bbl, which I swapped to a 4bbl when I bought the boat. I added a Edelbrock 1409 600cfm marine carb at that time
Heads are casting #14096217, 64 cc with what looks like push in style studs
It has the factory Roller cam setup in the boat currently. Manual shows the cam as #431-811658, with .394/.404 lift
Piston are a slight dish with 4 valve reliefs,
What I have is a set of freshened 12558062 Vortec heads, also 64cc.Stock springs and keepers, no upgrades. Pistons on the Vortec engine I got the heads from are the same style as my engine, slight dish, 4 valve reliefs.
Wanting to swap the Vortec heads on, and wondering if a cam swap would be the only way to see a real power increase? Or would the heads/intake be a nice addition alone?
I know I will need a new intake manifold. I have been looking at the Edelbrock Performer(idle-5000rpm) and the RPM Air Gap(1500-6500RPM)
My main questions are, would the original cam be ok, with the head upgrade? Or should I upgrade it? Would I need to change the rocker studs to screw in style, and would a RPM Air Gap be better then a performer Intake? Would like to see about 300hp out of the engine
Thanks for any input.
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