Offshoreonly.com - camshaft for marine vortec 350

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Quote:

Originally Posted by 79formula (Post 4000444)

here is your cam. http://www.summitracing.com/parts/nal-14097395 I would go bigger. And also its a 109 cam, most marine cams are 112 lobe separation as to avoid reversion.

This cam is the stock cam on many Merc motors. My 1995 350 Mag EFI/MP had this cam. In spite of the 109 LSA it doesn't cause reversion. The LSA coupled with intake/exhaust overlap events and overall duration duration influence reversion. The duration on that cam is very very mild.

Quote:

Originally Posted by sprink58 (Post 4000890)

You are correct...any lift over about .480 causes a bind in the lighter stock spring. Larger more robust springs require relieving the spring pocket to accept a more substantial and larger diameter spring.

I have been told .480 is the limit stock. I have heard of guys running ls6 beehive valvesprings to get over .500 with no machine work.

Many good suggestions here. Don't count out a gm lt4 hot cam. Roller lifter 112 separation 218/228 at .050 and .525 lift with 1.6:1 rockers. Beehive springs require no machine work. This makes very good power on a vortec 350 as .525 lift is where they make max flow. I have turned mine 5200 to 5700 depending on prop but have settled in at 5200. I gained about 1000 rpm over original motor before repropping so this isnt bench racing

Quote:

Originally Posted by Mr Maine (Post 4001645)

Although it would require some machine work due to lift on a Vortec head another cam option is the Crower LM00483, similar to the LT4 but on a 114 lsa and its .221/.230 with .525/.545" on a 1.5 rocker.

I thought long and hard about mine before I pulled the trigger on it. I wanted to be able to spin past 5000 RPM making power but without giving up low end torque.

The Comp Xtreme Marine 270 Roller worked out well in my application. In a twin engine application I am really pleased with the torque these engines build below 3000 RPM. With 23" Mirage props running thru Bravo One 1.5 ratio drives in a fully fueled 6000# boat I can run 35 MPH at 2000 RPM and 50 MPH at 3000 RPM !! That's not even into the secondaries of the carburetors!! The specs on these cams are:

Grind Number XM270HR

Lift Intake .495 Exhaust .503
Duration Intake 270* Exhaust 276*
Lobe Separation 112*

I am running Comp Needle Bearing 1.5 Roller rockers and make power thru 5500 RPM which seems to be a good all around set up for me. The combination of Vortec Heads with Roller Cams really gives the man utilizing Small Block Chevy's many options to push power and torque well above the 400 mark with ease. Technology moves ahead!!

Quote:

Originally Posted by Trash (Post 4002031)

Ive went back and fixed the link, Have a read a very well articulated thread on lift with vortec's...ls6 springs...compcams 050 retainers and your good to go.

http://www.pacificp.com/forum/viewto...38779cfdf2de0e

Quote:

Originally Posted by Pliant (Post 4002151)

Best of luck. I would be careful about spring selection and proper seat and open pressure with the higher lift roller cams.