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On a 392, it looks like, at least in theory, you could stab in a NSR cam without doing anything else to the engine. Leave the MDS, lifters, and pushrods alone. Anyone done it?
 

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On a 392, it looks like, at least in theory, you could stab in a NSR cam without doing anything else to the engine. Leave the MDS, lifters, and pushrods alone. Anyone done it?
I'm doing this exact mod at the end of the month.

I purchased the NSR Stage 3 Lope cam from Modern Muscle.

222/230 w/ 114 LSA.

When going with a more aggressive cam, you really need to look at swapping to the Hellcat lifters.

I purchased the MDS delete kit, which includes a full set of Hellcat lifters, trays and MDS solenoid delete plugs.

I also purchased 0.080 wall MMX pushrods. Manley also makes a set of these. While the factory pushrods are fine with the stock cam, it is ideal to go with a stiffer pushrod.
 

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Discussion Starter #3
Why do you have to change lifters and pushrods ?
 

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MDS lifters are prone to collapsing with an aggressive cam, I would recommend non mds lifters unless the manufacturer specifically says you dont need them.

Typically you dont need pushrods for any of these off the shelf grinds but some companies suggest them and indeed they are safer.

My motto is if the engine is coming apart, might as well add in the little things and save on labor later. Even if that means you need to save up for longer. That being said, I did replace the lifters when I did my cam swap but waited and did pushrods about 8 months later.
 

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Discussion Starter #5
My line of thinking is that it's the stiffer valve springs that add load to the lifters and pushrods with bigger cams. It's not the cam itself. Holding the valve open longer with a longer duration cam should not change the load on the lifters or the pushrods. I guess you could argue that the new cam will move the powerband up and the engine may attain a higher useful RPM (and more frequently), and higher RPM does increase valvetrain loading.

If the lobe ramp-rate is a lot more aggressive, I guess that could do it too - but that can only change so much without eating whatever parts you use.

Just wondering if anybody has tried it.

If I sold MDS delete kits, upgraded lifters, and better push rods, I would certainly encourage you to buy them.
 

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I did the Comp 270, and I install the cam, springs and push rods, then removed the push rods as my tuner didn't like the longer push rods in my application. I routinely wind my car out to 6k plus rpms with the factory push rods. I have a M6 car so I already didn't have MDS. I am interested in finding out if the Hellcat lifters make that much more of a difference, if so, I may swap to them next time I tear my engine apart.
 

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If they are traditional lifters they usually are changed because of the pattern established when the cam/lifters are run in initially....That happens usually in the first half hour or so of start-up...If roller lifters it may not matter...You can re-surface traditional lifters and reuse them that way...But its like building a house with rusty nails...


Meh auto mechanics was a long time ago for me lol...
 

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What is the duration at .050" and the LSA of the stock 392 cam? Does anyone know that?
Intake:
Lift @ valve .577"
Duration: 286*

Exhaust:
Lift @ valve: .537
Duration: 288*

LSA: 121

Valve overlap: 46*

These are from Chryslers spec sheets when the '11 392 engine came into production.
 
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