Mercury 409 MPI

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10-19-2022 | 06:50 AM

#41

AllDodge

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Joined: Nov 2009

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From: KY

IMO the old saying is still true, no replacement for displacement when it comes to low end torque

10-19-2022 | 02:12 PM

#42

cheech

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Quote:

Originally Posted by hogie roll

The exhaust scavenging benefit of a flat plane crank is not trivial. It would be worth 35 ft lbs of torque on the LT5 I recall.

The only trick is keeping the vibes in check.

Wonder if that's what the new engine mount ordeal is in this 409 situation?
I think that's one of the keys in the new Z06 is special mounts to combat the vibrations.

10-19-2022 | 02:17 PM

#43

cheech

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Quote:

Originally Posted by RSCHAP1

Wondering if any connection what so ever to newest Z06 Vette.
Only other thing I have heard domestically with flat plane crank.
Coincidence?
Doubt it, but still wonder...

Fords 2015 GT350 had flat plane also.
If I remember right that engine got nixed for timing chain issues.

10-19-2022 | 03:06 PM

#44

hogie roll

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From: St. Pete Beach, FL

Quote:

Originally Posted by SB

In a boat with standard wet non tuned cast iron manifolds ?

I would say yes. Otherwise there is no reason to do it.

But also, at higher engine speeds, the short exhaust runners get closer to the tuning window. I noticed some wake boats have a true SBC cast header with a cat integrated.

Maybe reversion improves too?

Last edited by hogie roll; 10-19-2022 at 03:11 PM.

10-19-2022 | 03:07 PM

#45

hogie roll

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From: St. Pete Beach, FL

Quote:

Originally Posted by RSCHAP1

Wondering if any connection what so ever to newest Z06 Vette.
Only other thing I have heard domestically with flat plane crank.
Coincidence?
Doubt it, but still wonder...

Doubt it.

10-19-2022 | 03:08 PM

#46

hogie roll

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Posts: 3,863

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From: St. Pete Beach, FL

Quote:

Originally Posted by cheech

Wonder if that's what the new engine mount ordeal is in this 409 situation?
I think that's one of the keys in the new Z06 is special mounts to combat the vibrations.

I would bet it is.