Looking for a good 350 Vortec setup.
07-01-2015 | 07:36 AM
#11
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From: dfw texas
If you have the marine roller grind in there now ,its prob already a ht383 crate cam. The 7395.. Merc used those in vortecs from the 305 2bbl through the 5.7 scorpion.i believe the stroker motors with a little more exhaust runner move up to a bit more profile.i believe your vortec 4bbl intakes are going to be geared towards a holley square pattern i would go for a 700 or 750 vac secondary depending on what kind of rpm you can ultimately pull out of it.
pretty basic easy foolproof 300 horse at 5k rpm or so. Indmar selects slightly different gm piston p/n with a few other little things and gets a bit more from the same basic set up ,but once you exeed that 300 horse mark with your cammed truck motor the laws of diminishing returns start to kick in real fast
pretty basic easy foolproof 300 horse at 5k rpm or so. Indmar selects slightly different gm piston p/n with a few other little things and gets a bit more from the same basic set up ,but once you exeed that 300 horse mark with your cammed truck motor the laws of diminishing returns start to kick in real fast
07-01-2015 | 10:20 PM
#13
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Thanks for the info. Opened up the bottom of the Engine I plan on using for my build. Cylinders look really nice with no ridge. Will use a bore gauge to see how out of round or worn they are. The engine spun the front 2 main bearings. Rod bearings look ok so far, but looks like the crank is junk. The front journal has a taper to it from the bearing walking forward. It was almost touching the lower timing chain gear.
07-01-2015 | 11:10 PM
#14
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I have a 1997 Larson 206 Sei with a 1997 Mercruiser 350 that started out as a 2bbl. 210hp. I swapped to a 4 bbl intake and a Edelbrock 1409 carb when I bought the boat, which helped some on top end speed. The engine does have a roller cam in it already, and has the non vortec 14096217, 64cc heads on it. I bought a freshened set of 12558062 Vortec heads, that are also 64cc. Have been doing some reading here, and a couple other forums, and want to get some ideas what intake and cam to add to the engine.
According to the mercruiser manual I am looking at, it shows my cam is part #431-811658 at .394/.404 lift.
The cam I am looking at is the GM# 14097395, which is .431/.451 lift, and has .109 lobe separation.
I have read Vortec head valve springs can't handle much over .460 without some spring/seat/keeper mods
Does this cam look decent?
Also, with that lift, etc, would I need to get the rocker studs machined for screw in style?
Would the cam swap net me much more HP? Or would I be better to stay with the factory roller cam
.
According to the mercruiser manual I am looking at, it shows my cam is part #431-811658 at .394/.404 lift.
The cam I am looking at is the GM# 14097395, which is .431/.451 lift, and has .109 lobe separation.
I have read Vortec head valve springs can't handle much over .460 without some spring/seat/keeper mods
Does this cam look decent?
Also, with that lift, etc, would I need to get the rocker studs machined for screw in style?
Would the cam swap net me much more HP? Or would I be better to stay with the factory roller cam
.
The GM 395 cam you mentioned is used in nearly all of the higher hp small blocks. My 1995 350 EFI Mag had that cam, I tore down a 2000 Malibu ski boat 350 (had Vortec heads) and it too had that camshaft. It is very common. You would not need any special head work with that cam. It pulls good in the mid-range but is not a high rpm cam.
07-01-2015 | 11:14 PM
#15
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[QUOTE=rsvert89;4317250]On a GPS, I can run 55 right now on a nice calm water day, trimmed up, running 4500-4600 rpm with a 1.62 ratio Alpha One Gen 2 and a Turning Point 21P Stainless prop./QUOTE]
One of the numbers is off as this makes your slip virtually 0-2%.
One of the numbers is off as this makes your slip virtually 0-2%.
07-02-2015 | 12:04 AM
#16
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From: dfw texas
Merc pn on the first roller cam 059 head vortec 305 carb 2bbl and up i will bet is the same up the mid 2000 mie scorpion.. Dont look at specs from service manual . either just the numbers on the back of the cam . They dont like to sit in watery oil but are cheap. If you dont already have one . Then they are free
