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I have a 2015 Shaker, 5.7 m6. Looking to swamp cams. Anyone have any driving experience with either the 270 or 274? Trying to figure out which one to go with.

On YouTube the 274 seems to have a much more aggressive sounding lope, that I admit I kinda like...

https://youtu.be/69XYDmVmccs


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I can enlighten you on a little cam know how.
Don't know either of those specs cams.
Just remember this:
The bigger those numbers are, the shorter time the valves are closed. Those are duration numbers.
Smaller numbers mean higher RPM power and vice versa.
Another factor is the center line the cam lobes are on.
Most of that camming sound is the result of the center line number. Most people don't even know about it or talk much about it. A stock cam will generally have a high center of about 116 to 114.
That one was probably around 112 or so just by the sound.
This wasn't mentioned either--Lift. The hemis already have a decent lift. Too much lift and now you need valve springs. PCM mods--Money money money.
You have to compromise with what you want. Low end or high end.
Factory usually compromise with mid-to high range.
First number of duration always lower than the second.
So you can see that there are many variables in store.
One thing I'm not sure of is how the variable valve timing is going to act when you start changing things up too much. So there's another factor. More research required on that one.

First decide for yourself where you want the most power. Go from there. And you cant have both.

In my big block mopar days I always opted for low end power. In my example of old days, I had a 1969--383 magnum ran with a Crower cam .510 lift in/out. 280.290 duration, 108 center line. It idled at 1800 RPM. Sounded and ran great. The headers would glow red 14 inches from the heads out. Always amazed people at night. And it only got 8 MPG average on street. That was a very well built engine I drag raced. Sure miss those days...
I wouldn't do that however in my SRT.
 

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So I can chime in on the Comp 270 VVT. I did this for my 2013 5.7 M6 R/T Challenger. I also did a 4.29 gear swap and a few other mods towards the end of last summer. For starters you are correct that the 274 has a much better sound. The 270 doesn't lope as much, but I can attest to the performance. When I ran my car at the beginning of the race season last year, prior to breaking the transmission, the best ET I put up on a 50 shot of N2O was a 12.26, @ 109. Since I put this cam in my car ( with a broken transmission last year) I've been a best of 12.3x's @ 118. This is on a very badly used set of Hoosier drag radials......... On motor alone I went 13.2X' @ 110 with the Comp 270..... I can take the car all the way out to 7k RPM, although I shift at 6500 when I'm racing. The cam makes power from 2k all the way to redline. From the research I did, the 274 makes power from 3k to 7500 rpms. I didn't think I'd ever see 7500 on the track so I opted for the 270. I'm happy with the over all performance, and to get the lope that I want, I think I'm going to put on a set of Flow Master mufflers and delete the resonators on the Corsa. As a matter of reference with the Comp 270 you do need to upgrade your valve springs and keepers. I bought an entire kit, that came with Head Gaskets, new head bolts, springs and keepers. I did the install myself with the exception of installing the springs. I had this done by my local machinist as he also ported, polished and performed a valve job on my heads. Lastly when doing a VVT cam swap you will need the cam Phaser limiter, this will stop the PCM from advancing or retarding the cam too much. Custom tuning is a must, so factor this in before you do this work. I had to scramble at the end of my install to find a tuner. Thankfully Jay Green is amazing and I was able to get back on the road before the weekend was over when I completed the job.
 

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Dak,
Did you do a before and after dyno? Curious as to the difference in your low end torque, and if you were able to minimize any loss with the tune.


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Dak,
Did you do a before and after dyno? Curious as to the difference in your low end torque, and if you were able to minimize any loss with the tune.


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No didn’t do get any before or after dyno numbers. I didn’t have time to get it dynoed, I was trying to make the MSHS event in Richmond. Honestly I still haven’t had my car on a dyno, I’ve always subscribe to the theory if I obtain lower ET’s in the 1320, then I’ve found a way to make more power efficiently. One day I’ll get my combination Dynoed just not in the immediate future.


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Wondered if you guys could shed any light on my cam. The mechanic I purchased the car from was a mechanic at a dealership who worked on their high end performance cars - Hellcats, SRT's etc... You can see all the mods he has done in my cars profile. He said he has a 274 cam in it - but the lope does not sound like other lopes, its not as heavy, which I like. If any of you can listen to this clip and let me know your thoughts I'd greatly appreciate it. You all have much more experience and knowledge on this subject matter than I do and would greatly appreciate your feedback.

 

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Sounds like idle is too high to really get the big cam sound
 

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Sounds like idle is too high to really get the big cam sound
Thanks for your feedback. Yea I was kind of thinking the same thing. It was tuned by High Horse Performance prior to me purchasing it. In spring I will be taking it the performance shop here in MI and they will tune it for me. So we'll see what they think.
 

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Thanks for your feedback. Yea I was kind of thinking the same thing. It was tuned by High Horse Performance prior to me purchasing it. In spring I will be taking it the performance shop here in MI and they will tune it for me. So we'll see what they think.
If you have the hand held that is paired to the PCM and know the tuner, then they may be able to email a lower rpm idle to you if that is the only change you want.
 

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^^^^ agreed with what was said above. If you have a custom tune don’t pay to have another one made just for sound purposes. Get it on a dyno and or to a track. It sounds to me like it is certainly cammed with something. It’s a 6.4 so It sounds throatier than a 5.7 to begin with.


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If you have the hand held that is paired to the PCM and know the tuner, then they may be able to email a lower rpm idle to you if that is the only change you want.
Thanks for the feedback Destroyer. I don't have the hand held tuner. The mechanic did leave it in the car but the dealership took it out. Hence the reason I'll be taking it to the shop here in MI for a new tune and that way they'll have the tune saved and we can adjust it.
 

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I can enlighten you on a little cam know how.
Don't know either of those specs cams.
Just remember this:
The bigger those numbers are, the shorter time the valves are closed. Those are duration numbers.
Smaller numbers mean higher RPM power and vice versa.
Another factor is the center line the cam lobes are on.
Most of that camming sound is the result of the center line number. Most people don't even know about it or talk much about it. A stock cam will generally have a high center of about 116 to 114.
That one was probably around 112 or so just by the sound.
This wasn't mentioned either--Lift. The hemis already have a decent lift. Too much lift and now you need valve springs. PCM mods--Money money money.
You have to compromise with what you want. Low end or high end.
Factory usually compromise with mid-to high range.
First number of duration always lower than the second.
More intake duration moves the peak horsepower “up” in the rpm range if the rest of the engine flows well enough to get there - this is related to the intake closing point. You can add a little duration without moving the intake closing point by advancing the whole cam profile.

As the intake valve closes later in the compression stroke, you tend to get some low rpm reversion. The piston pushes the charge back out before the valve closes to trap it. This reduces cylinder filling and if you had a compression tester in a cylinder while it was running, you see low rpm dynamic compression go DOWN. To offset this, static compression ratio is generally increased.

The first number is intake duration and the second is exhaust duration. The exhaust is under much higher pressure and tends to be easier to get out of the cylinder. That’s why most (if not all) exhaust valves and ports are smaller than the intake valves and exhaust duration is generally shorter on most (but not all) naturally aspirated engines.

More lift is almost always better for performance (torque) within the limits of the mechanical parts. Lift is hard on stuff. Valvesprings, pushrods, valve guides - all of it. And too much lift can cause valve to piston interference if the pistons don’t have clearance cuts that are deep enough. Short duration and high lift is great for torque with a low rpm limit, but increases valvetrain loading tremendously. That’s why you don’t tend to see many grinds like that.
 

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Not to keep beating a dead horse. But, I'm highly interested in putting in the 274 cam (with phaser) in my RT. I was planning on doing all the work, but while I was in there I was going to upgrade springs, rollers and push rods. I was curious if anyone has done this mod before and was interested on the level of difficulty?

I know the safe route is to taking it to an actual shop but I've done all the work to her so far and kind of like to keep that pride. Thank you!
 

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Not sure if you have seen this yet but this is the direction i would follow if i ever to do mine. also show you how to install the Phase limiter kit.







Not to keep beating a dead horse. But, I'm highly interested in putting in the 274 cam (with phaser) in my RT. I was planning on doing all the work, but while I was in there I was going to upgrade springs, rollers and push rods. I was curious if anyone has done this mod before and was interested on the level of difficulty?

I know the safe route is to taking it to an actual shop but I've done all the work to her so far and kind of like to keep that pride. Thank you!
 

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I have seen that video, every informative. I also purchased a book called how to rebuild gen 3 hemi. Seems to pretty detailed book. I think I found my spring/summer project.
 

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I have a 2015 Shaker, 5.7 m6. Looking to swamp cams. Anyone have any driving experience with either the 270 or 274? Trying to figure out which one to go with.

On YouTube the 274 seems to have a much more aggressive sounding lope, that I admit I kinda like...

https://youtu.be/69XYDmVmccs


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I'm running the 274 in my car, it runs great.. People tend to think it's too big and you will lose low end power but that's not the case. I was actually a little concerned when I went for it. However the VVT allows for a more aggressive cam without losing the bottom end power. You will need a good tuner though. I had a tune from one supplier and it bucked like crazy under 1500 RPMs with the other tuner (HHP) I can literally idle in gear and have really good low-end power up through 6800 RPMs.

There is a video on the forum here where I guys shows the tuning of a 274 and he shows there is actually HP and torque gains down low with the proper VVT settings. If I can find it I will pop it in here.

Found it... go to page 3 post #28. https://www.challengertalk.com/forums/f5/400-whp-naturally-aspirated-waste-money-mod-667425/index3.html
 

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Not to keep beating a dead horse. But, I'm highly interested in putting in the 274 cam (with phaser) in my RT. I was planning on doing all the work, but while I was in there I was going to upgrade springs, rollers and push rods. I was curious if anyone has done this mod before and was interested on the level of difficulty?

I know the safe route is to taking it to an actual shop but I've done all the work to her so far and kind of like to keep that pride. Thank you!
in the 5.7, you're going to have to change the springs due to the higher lift (coil binding issue with stock 5.7 springs)

Push rods are a wise step as you're going to have higher rate springs over stock.

Also get stronger spring retainers and you'll need seat locator cups as well. The stock stem locks / keepers are fine, don't need to change those.

For the 5.7, go with the 270 - it takes a very experienced tuner to get the 274 dialed in correctly. Even Comp mentions the 274 is not recommended for the 5.7s. Its intended for larger displacement engines.

The phaser limiter is a must with those cams. The kits have a clamp / retainer to hold the spring under tension while you disassemble the phaser to insert the limiter block.

Did my first limiter install for a 392 engine cam swap - no big deal.

It takes about 22 hours (from very start to everything back together) for the whole job. Valve springs take the most time (I use compressed air to hold valves shut) when doing this with heads on the engine.

FYI - the 392 engine is very similar to the 5.7, except that there's a stud / nut mount off the windage tray that requires all the oil pan bolts be removed, remove steering rack bolts (lower it, don't need to remove) drop the oil pan down 3" to access the nut securing the oil pickup tube.

the radiator drops from below - the lower radiator support is held in with 4 bolts - the main belly pan and front belly pans are removed to have access to everything.
-the combo a/c condenser / p/s cooler ('09 - '14) / A/T cooler must be unbolted from the radiator (4 small bolts) and leave all the hoses connected.

The nose doesn't need to be removed to r & r the cam...the '08 - '14 style have 3" remaining behind grille when you've removed the cam.
the '15+ style requires you angle the cam a bit to clear the backside of the grille.
-I've done it on both versions

Otherwise, removing the nose is a 2 person job and add more hours. You want a helper to prevent scratching / chipping any painted surfaces
 

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FYI - the 392 engine is very similar to the 5.7, except that there's a stud / nut mount off the windage tray that requires all the oil pan bolts be removed, remove steering rack bolts (lower it, don't need to remove) drop the oil pan down 3" to access the nut securing the oil pickup tube.


A little trick you can use on this part quoted above.. Set the #1 cylinder on TDC. Mark the timing gear and the timing chain you can also get to the crank gear just enough to mark it there too just in case something happens and it moves. Then you can just zip tie the timing chain so ist snug around the crank timing gear and lay it off to the side over the tensioner. That saves all of the hassle of taking off the oil pump.
 
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