2004 GM vortec information?

[Ruune]

absolutely. I cut through all the BS and ran some numbers, which is why I stuck w/ the MAG MPI. To me, it was a choice between the 6.0L and the 315 horse 5.7L. As it was too hard to make a direct comparison with the possible exception of the PCM Excalibur, which boasts 430ft-lbs- I couldnt get any numbers on the torque for comparison between the MAG MPI and the black scorpion or the Tigé/Vortech 5.7L. I thought about getting the PCM, but the price tag on that was pretty steep.

[Tige M.D.]

Horse power, torque bla, bla, bla.
Look guys, it's a numbers game. If you have 315hp then I have to have 325hp and so on...
All of these engines come out of the same door at GM, just get into different trucks. Yes, they do have different bolt on's but how much is 5-10hp gonna change a boats performance? NMMA requires a 10% + or - in advertised hp. GM advertises the 5.7 crate motor they sell to Indmar at 295hp. Pretty hard to bolt on 40hp with out a blower, turbo or nitrous. As for torque, I have yet to find someone at Merc to put a number in writing.
If I were to buy a Tige today it would have a vortec 335mpi (Marine Power) pushing it. Eddie(owner of Marine Power) and his son Walter will do whatever it takes to keep you happy with their motor package.
The corrosion problem stated earlier, I have yet to see.

[Ruune]

how come the PCM excalibur is rated at 435 ft-lbs of torque, vs the merc black scorpion 350 is rated at 365 ft-lbs?
http://www.pleasurecraft.com/57.html

http://www.mercurymarine.com/black_scorpion_-_330_hp

I'm assuming they've both got a 1.23:1 transmission, and are rated at the prop.

(the merc website appears to be having trouble right now, but I believe the torque rating is at the bottom of the page, under "specs.")

[Tige M.D.]

Mercury Marine rates everything at the prop. As far as I know they are the only ones that actually do this. From what I've heard this last fall at Mercury school they are about to change that. They want to sound more competetive.
The gear ratio would depend on the model of boat v-drive vs. direct drive.

[Tige M.D.]

I just looked at both of the links you provided and I am suprised to see PCM rating hp and torque at the prop. Too bad neither tells the power band. Gobs of Hp and torque at 4800rpm doesn't do use much good.
If I sound negative towards Merc and
PCM it's becauseI truely believe Marine Power is the all around better package. I personally would'nt put a Mercruiser in my boat if it was free. Too many problems on too many boats.

[Ruune]

something else I just noticed... the PCM is rated w/ a 1.23:1 transmission, and the merc is rated w/ a 1.0:1 tranny. I wonder if both are on a direct drive or V-drive, and if V-drive- what tranny is on there?

[OldSkier]

I think there's a bit of smoke and mirrors with the rating of torque at the prop AFTER going thru a 1.23:1 reduction gear. HP is simply a function of torque X RPM.

My bet is that the real engine torque is 435 ft-lbs divided by 1.23 = 354 ft-lbs. at the crank at motor rpm. This is more in line with the blackscorpion at 365 ft-lbs.

Regardless, I agree with Tige MD. You/we need to understand the torque through the ENTIRE motor RPM range to make an informed decision. AND, to compare apples to apples.... we can't add confusion with comparing different gear ratios.

But.....the mfg's just won't release that kind of info to the marine world like they do in the auto world. Too bad. So, we have to sift through the confusion...

[blr]

ruune - i sure hope the corrosion thing is a rumor or a single incident that got on the grape vine highway. based on my dealers comments which were identical to Tige MD's, I went with the 6.0 375HP Marine power. my dealer also said that they drove both the PCM and MP side by side and the only way that they could tell the difference is by pulling up the "lid" and looking at them. i guess i'll know in a couple of weeks how it perfroms, but time will only tell me on the corrosion and reliability. i'll keep you posted. btw- i too thought the pcm price was quite steep for ?????