Merc 377 Scorpion top ends?
08-14-2017, 12:31 PM
#1
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Merc 377 Scorpion top ends?
I have blue 377 scorpions with 290hrs on them. As far as I know, they had whipples installed at around 100hrs. Looking for when I should do top ends. No current issues, just curious.
Tim
Tim
08-14-2017, 01:31 PM
#2
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I can't find cam or valve spring specs for that motor, but it is custom ground by crane. 300 hrs is usually considered the limit for high perf valve springs. When in doubt, change em out...
08-16-2017, 08:04 PM
#6
The lift was not .6 something. It was low .5, like .51x/.51x or in that ball park. I've seen the specs just can't fine them. 2.05 and 1.6 exhaust, so yes big on the intake.
08-16-2017, 08:43 PM
#7
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The 400hpScorpions ?
If so, I found a quote from myself years ago:
If so, I found a quote from myself years ago:
Originally Posted by sb
Run down on the 383cid Scorpion:
6000+rpm rev limit.
hand
5600-6000 rpm recommended operating rpm at WOT
Tunnel ram intake
RHS heads w/ 2.08/1.60 valves
.575, .596 lift HR cam with 1.6 roller rockers
Forged steel crankshaft
forged pistons
9.6:1 compression - 91 octane fuel minimum
CMI headers
In case I made a typo click here: http://sites.mercurymarine.com/porta..._schema=PORTAL
and make sure to click on the .pdf containing the rest of the build info.
6000+rpm rev limit.
hand5600-6000 rpm recommended operating rpm at WOT
Tunnel ram intake
RHS heads w/ 2.08/1.60 valves
.575, .596 lift HR cam with 1.6 roller rockers
Forged steel crankshaft
forged pistons
9.6:1 compression - 91 octane fuel minimum
CMI headers
In case I made a typo click here: http://sites.mercurymarine.com/porta..._schema=PORTAL
and make sure to click on the .pdf containing the rest of the build info.
08-16-2017, 08:45 PM
#8
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08-16-2017, 08:53 PM
#9
Were the scorpions rated 400 horse? Seems like a 383 with sb specs above would be more than 400.
But then again with a bigger boat it seems a big block is faster even if it has less horsepower on paper. Case in point a 415hp 502 is usualy faster than a 400ish horse 383.
But then again with a bigger boat it seems a big block is faster even if it has less horsepower on paper. Case in point a 415hp 502 is usualy faster than a 400ish horse 383.
08-16-2017, 09:04 PM
#10
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I believe there where different Scorpions..not sure..?????? .that's why I made sure to put up which one I was referencing. The 400HP Scorpions.
And yeh, I agree,most dyno's would show more than 400hp with that set-up...I'm sure. Remember, Merc has to put power ratings where they will sell not only this motor but other motors. ust like the 525EFImaking 560hp or so.
And yeh, I agree,most dyno's would show more than 400hp with that set-up...I'm sure. Remember, Merc has to put power ratings where they will sell not only this motor but other motors. ust like the 525EFImaking 560hp or so.
