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A new shop opened up here that can stroke motors out, so now I am thinking about stroking my 5.7 to the 392. I know many of you on these forums have done this, so what kind of power does this put out? Is it comparable to the new SRT 392? Also, How much did it cost to bore out the engine and install a kit from arrington? Finally, does putting the stroke in take the life of the engine away, or is it a small enough stroke to not make a difference?

Thanks in advance.
 

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Increasing the stroke of any motor can reduce the lifespan. There are a lot of threads out on strokers--just search around.

As far as just purchasing the rotating assembly and having a machine shop the handle the other side of the coin for you, you can certainly do that but I wouldn't recommend it unless you have some prior experience in this arena.
 

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It's just helluva easier to purchase a complete stroker package from a vendor on here. The Arrington kits are stroker internals only, they do not require to block to be bored. So if you're comfortable swapping the engine internals, you certainly can do it yourself. You can also talk to Andy at PWR, he's done tons of stroked motors, I'm sure he can hook you up.

It'd be very hard to compare a do it yourself stroker kit to one that Dodge offers as typically you wouldn't JUST stroke it. Once you add a Cam/Heads combo, decent exhaust you'll definitely trump what Dodge offers since Dodge has very strict emissions parameters to maintain.
 

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It's just helluva easier to purchase a complete stroker package from a vendor on here. The Arrington kits are stroker internals only, they do not require to block to be bored. So if you're comfortable swapping the engine internals, you certainly can do it yourself. You can also talk to Andy at PWR, he's done tons of stroked motors, I'm sure he can hook you up.

It'd be very hard to compare a do it yourself stroker kit to one that Dodge offers as typically you wouldn't JUST stroke it. Once you add a Cam/Heads combo, decent exhaust you'll definitely trump what Dodge offers since Dodge has very strict emissions parameters to maintain.
I'm curious about what you ment about arringtons stroker rotating assembly's it sounds like you said you can buy there 392 kit and you don't need to bore the block and you just swap internals???
 

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This is the big headache of tuning, this is why I went above my budget just to get an original 392.
I am waiting for the PCM decoding solution so we go for it and have some more HP :)
 

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I would go with one of the vendors who support this forum. They have all the experience you want in an engine builder. Plus, it rewards companies who support our forum. Keep it in-house.
 

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You definitely will want to do some research. There's a good book called "How to Build Big Inch Small Block Mopars" that's for older LA and Magnum small blocks, but it's a great read to get the general idea of what all will be involved. Not sure if there's a book out yet on the modern Hemis.

There's also tons of videos on YouTube showing various stages of block assembly, machining, etc., that are very fascinating to watch.

Essentially, you will be tearing the engine down to the very core block and rebuilding it with mostly new internals. It can get pretty pricey, and there are lots of shops that well tell you they can do it but lack the real expertise to do it right. The benefit of going with a well known builder is that they typically do a good job, out they don't get recommendations and will usually get slammed on the various forums. That assurance of quality can be well worth the added price tag. Lots of guys recommend going that route as a "open your wallet and cry, but only cry once" philosophy.

If you're really planning on doing it yourself and you've never done it before, you'll definitely want a person to guide you through the process. Find a local shop with a good reputation and have them do anything you don't feel comfortable with it can't do based on the specialty tools or skill involved.

Usually, if the block is newer, one can get away with minimal block prep cost. They typically don't have to be bored out larger if the block is "fresh" but one should always have it inspected and checked to make sure it's a good candidate to be stroked. if the block doesn't have enough "meat" to be bored out later on, it might not be a wise investment to stroke that particular engine. Although this seems to be less and less a problem as manufacturing processes improve, so too does the manufacturer of the blocks try to save money by reducing the raw materials used in the block casting, so having a block sonic checked is never a bad investment, IMO.

There may be other costs involved beyond buying the kit like block clearancing, decking, balancing three rotating assembly, pressing pins, etc. that the shade tree mechanic probably can't do on their own, so don't forget to factor in that cost, as well as things like purchasing or renting an engine stand or block hoist.

If done correctly, there's no reason a stroked engine can't last a long as a stock engine, save that folks that invest in stroker motors tend to be a bit harder on their vehicles than the typical driver.


Understand also that two engines with the same displacement (ie a factory 392ci and a stroked 392ci from a 345ci engine) don't always make the same power even if the parts like heads and camshafts are identical. The stroke versus bore size makes a difference on how the power gets applied to the wheels. A stroked 392ci may make more torque but less high end HP based on it's bore size versus it's stroke compared to the factory offered 392s bore and stroke. I don't know the bore and stroke measurements offhand of either of those particular combinations, but typically a longer stroke produces more torque (and HP, since HP is a function of torque) down low, but takes a bit longer to rev up to the higher RPMs. If Chrysler did in fact just stroke out a 345ci engine to make their 392ci Hemi, then you could reasonably expect similar performance with the matching heads, cam, intake manifold, exhaust, etc.
 

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I toyed with the idea of stroking my motor when I was window shopping for forged internals. The main thing that swayed me from doing it were:
1)adding cubes and not being able to match a cam due to VVT
2)the modifications to the block itself
3)the added cost of heads to match the added cubes
4)the fact that I can compensate boost for the extra cubes and adjust it up or down as desired (can't adjust the cubes!)
 

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I've been trying to track down a representative dyno chart for a stroked 5.7 L Hemi. Anybody seen one or have one to share?
 
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