Looking for info on 340 Torker performance mods

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Brooks James

Brooks James

VET, CPT, Huey Medevac Pilot
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Didn't see any
Plenty of everything else
Any pics would be wonderful

PXL_20241008_212741858.jpg
 
See if this helps any.


I know, I know, I said I wasn’t going to touch this ugly azz intake but I’m not happy at all with how the Speedmaster intake turned out. It’s going on 11 years since I retired from Millwright work and the thought of how long it’s been since I’ve had a tetanus shot kept creeping into my head. We...
“Ugly Betty” the ugliest Torquer intake on Earth
 
I just did some gasket matching on mine when I picked up the Eddy heads. No idea if it will make any noticeable change. I just like to do it . We'll see when it's all back together.

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From memory, the original Edel instructions said NOT to gasket match. Keeping the intake openings slightly smaller helped with reversion. Bigger is not always better....
 
Bewy said:
From memory, the original Edel instructions said NOT to gasket match. Keeping the intake openings slightly smaller helped with reversion. Bigger is not always better....
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Is that maybe a torque thing ?
 
It was about reversion. During overlap, exh gas 'reverses' direction & tries to enter the intake system, which is bad. Having some very slight port overhang disrupts this, without unduly affecting the incoming intake flow.
 
Depending upon your setup, you may find it likes the deeper plenum. My 408 got quicker when I added a spacer, I started out with a 1" and finally ended up with a 2".
 
Demonracer said:
Depending upon your setup, you may find it likes the deeper plenum. My 408 got quicker when I added a spacer, I started out with a 1" and finally ended up with a 2".
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I barely have room under the hood even with a drop base cleaner due to the height of the Chinese air gap

Thanks
 
My Demon is race only, so with the Harwood Pro Stock hood scoop I have plenty of room. Maybe think about an aftermarket glass hood with a six pack scoop or a 60's wedge or Hemi style scoop. Just a few thoughts if you are going to use a taller intake and/or a spacer.
 
Bewy said:
It was about reversion. During overlap, exh gas 'reverses' direction & tries to enter the intake system, which is bad. Having some very slight port overhang disrupts this, without unduly affecting the incoming intake flow.
Click to expand...


I have seen zero proof that making the manifold mismatch the head doing anything.

This came about because some shop in Arizona was doing big block Chevy’s with square port heads and oval port intakes. And it worked in that specific application.

It’s not universal. In fact DV is the only one I know still leg jumping that nonsense.

Several years ago Darin Morgan was on Drag Boss Garage and I specifically asked him this very question.

The short answer is it worked I that limited application but in almost all cases it doesn’t work.

If you are going to do the work to port the intake manifold make the ports match.

Especially on engines where the heads are the cork.

And IIRC that Chevy deal was some marine application.

That’s where this nonsense got its legs.
 
Newbomb Turk said:
I have seen zero proof that making the manifold mismatch the head doing anything.

This came about because some shop in Arizona was doing big block Chevy’s with square port heads and oval port intakes. And it worked in that specific application.

It’s not universal. In fact DV is the only one I know still leg jumping that nonsense.

Several years ago Darin Morgan was on Drag Boss Garage and I specifically asked him this very question.

The short answer is it worked I that limited application but in almost all cases it doesn’t work.

If you are going to do the work to port the intake manifold make the ports match.

Especially on engines where the heads are the cork.

And IIRC that Chevy deal was some marine application.

That’s where this nonsense got its legs.
Click to expand...
I am soooo glad you posted this, I haven't ever gotten a straight answer
In my case matching this offerhauser
For D64 273 eng 64-66
Notice the port poor casting
That need the floor and ceiling extended matched to a factory 360 magnum head
 
Newbomb Turk said:
I have seen zero proof that making the manifold mismatch the head doing anything.

This came about because some shop in Arizona was doing big block Chevy’s with square port heads and oval port intakes. And it worked in that specific application.

It’s not universal. In fact DV is the only one I know still leg jumping that nonsense.

Several years ago Darin Morgan was on Drag Boss Garage and I specifically asked him this very question.

The short answer is it worked I that limited application but in almost all cases it doesn’t work.

If you are going to do the work to port the intake manifold make the ports match.

Especially on engines where the heads are the cork.

And IIRC that Chevy deal was some marine application.

That’s where this nonsense got its legs.
Click to expand...
I am soooo glad you posted this, I haven't ever gotten a straight answer
In my case matching this offerhauser
For D64 273 eng 64-66
That need the floor and ceiling extended matched to a factory 360 magnum head
 
The only evidence I’ve ever seen come off a dyno (real evidence not hearsay) with regards to port matching was positive. It was A to B same manifold port matched vs not on the same engine. And it was worth a handful up top. Like 5-6 hp or so. I’ll have to see if I can find it.
 
Doesn't the Mopar Performance engine manual have some instructions?
 
Demonracer said:
Depending upon your setup, you may find it likes the deeper plenum. My 408 got quicker when I added a spacer, I started out with a 1" and finally ended up with a 2".
Click to expand...
I remember Joe Sherman saying he add a total of 7 spacers on an engine and every time he add one it made more power. Plenum volume dampens reversion.
Newbomb Turk said:
I have seen zero proof that making the manifold mismatch the head doing anything.

This came about because some shop in Arizona was doing big block Chevy’s with square port heads and oval port intakes. And it worked in that specific application.

It’s not universal. In fact DV is the only one I know still leg jumping that nonsense.

Several years ago Darin Morgan was on Drag Boss Garage and I specifically asked him this very question.

The short answer is it worked I that limited application but in almost all cases it doesn’t work.

If you are going to do the work to port the intake manifold make the ports match.

Especially on engines where the heads are the cork.

And IIRC that Chevy deal was some marine application.

That’s where this nonsense got its legs.
Click to expand...
The only way a mismatch would improve things is if it took fuel off the walls and re-entrained it.
 
Hysteric said:
I remember Joe Sherman saying he add a total of 7 spacers on an engine and every time he add one it made more power. Plenum volume dampens reversion.

The only way a mismatch would improve things is if it took fuel off the walls and re-entrained it.
Click to expand...


Yup. I do think there are better ways to get the fuel back into the air without a mismatch at the manifold.
 
Newbomb Turk said:
Yup. I do think there are better ways to get the fuel back into the air without a mismatch at the manifold.
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I know Larry Widmar says to make the intake port runner slightly smaller the the head port. When time and money permit I'm gonna make intake plates to sandwich between the head and manifold slightly smaller than the port in varying sizes to see if it improves the burn.
 
Hysteric said:
I know Larry Widmar says to make the intake port runner slightly smaller the the head port. When time and money permit I'm gonna make intake plates to sandwich between the head and manifold slightly smaller than the port in varying sizes to see if it improves the burn.
Click to expand...


How are you exactly going to monitor and test this. Pull a perfectly clean head off to look
for changes in carbon??? Dyno testing??? Or the best test of all track testing???
 
pittsburghracer said:
How are you exactly going to monitor and test this. Pull a perfectly clean head off to look
for changes in carbon??? Dyno testing??? Or the best test of all track testing???
Click to expand...
Various ways to monitor changes in combustion. A cheap and effective way is changes in spark plug deposits. Ideally a 5 Gas analyzer is best but an ignition scope will do too.

Even O2's will monitor changes in AFR accurately when you correspond them with spark plug reading.

You can even notice it when you have improved the burn just be the way the engine vibrates less and revs smoother.
 
Brooks James said:
Yes, maybe more, last one I saw was for LD340.
BTW what does LD stand for
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i'm guessing and this may be a bit of a stretch, but it *might* be "Late Design"

maybe it's something along the lines of:
D4B- Design 4 Barrel
LD4B- Late Design 4 Barrel
LD340- self explanatory
 
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