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Realistic HP numbers from a 392 (6.4) to 426 or 440 stroker upgrade & other questions

I have been tossing around the idea of upgrading my 2015 392 to a 426 or 440.

With research I have found that staying with the 392 or going up to the 426 is better if i plan on going up to a supercharger than a 440 because of angles and stuff.

So, my question is.. if I just upgraded to a 426 stroker or 440 and keep it NA what are the realistic HP levels I can reach?

If those numbers aren't enough (lol) and I then plan on supercharging it... would you guys recommend staying with the 392 or going up to the 426? I'm wondering if I supercharge it, will the added cost of the stoker kit be really be money better spent elsewhere.

Also, im looking to put about $10,000 into this, is my wishes out of my budget? maybe a little more for labor and if its worthwhile. I wont go overboard to get that last 25-40 hp but an extra 100-120 could sway me.

Thanks for any help you can give.
 

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I've seen API 426's dyno at a little over 500whp, and their most recent 440 build came in at 534whp.

I'm going with a 6psi Maggie, this should put me around 525whp. Add drop in pistons later and up the boost.
 

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FI gives far greater numbers than NA. It's more cost effective as well.

I feel you though, I would love an NA 440 under the hood, but it'll get its ass handed to it by a boosted 392, for cheaper as well.

And yes for parts and labor for both a stroker and a FI set up, I feel 10k is a bit on the low side. Like really low.
 

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A well tuned 150 or 200 hp nitrous kit should beat them both, be far cheaper, and only stress the engine when used.


I don't get the appeal of stroking to 426 or 440, aside from the numbers. Thick cylinder walls are always better than boring the block to the limit to add a few more cubes.
 

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I could be wrong but I think the extra cubes on API's 426 come from increasing the crank from 3.72 to 4.08.

I chose to go with a Maggie on my Scat Pack, when I get the car back I'll drive it for a year or so then do drop in pistons and up the boost. Then if I need more I can stroke it later.
 

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I could be wrong but I think the extra cubes on API's 426 come from increasing the crank from 3.72 to 4.08.

I chose to go with a Maggie on my Scat Pack, when I get the car back I'll drive it for a year or so then do drop in pistons and up the boost. Then if I need more I can stroke it later.

Why wait a year later to drop in forged pistons? I would do all forged internals on a supercharged 392 now..........I've heard too many horror stories of 392's blowing up with stock internals and boost. Just my 2 cents.
 
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Having a very recent build of a 6.1 -> 426 makes 513hp and 500tq with the torque curve just as flart as my desktop is awesome. Drive-ability is really good too even in heavy traffic with a 6M.

I don't get the FI is cheaper. You first have to forge the engine to insure it's reliable, this is the 426 stroker, but then you have to add the FI component which is another $8k - 20k depending on how you do it. Hmmm.

To those that boost without forged internals, you'll pay double down the road. The newer engines have really crappy internals and the top rings are so close to the top of the piston is takes little to crack them. Some detonation will do it. The cast pistons can't take a lot of heat or pressure both happen with boost. Add to that the current PCM's for these cars don't do boost natively so it's a nasty tweak to make that all play that can have some repercussions later on as well.

I can run a stroked engine wide open all day and not have any issues, a boosted engine will heat soak and if not properly built break if you try that. I don't think there's a bottle big enough to spray all day. But it is really easy to add spray to a stroker and for cheap that can give you an extra 250 shot for those "times", and those forged internals will handle it pretty well also.

Just wanted to point out a piece of the equasion everyone seems to leave out.

JMONSHO
 

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It wouldn't surprise me if they wouldn't do it, but if I was to try to get any shop to build a Hemi, it would be Tony Bischoff. He's a very intelligent builder of the Engine Masters series of Popular Hot Rodding. Our school competes against him and Jon Kaase every year and we hang with them. The modern Hemi isn't our specialty though.

Usually FI will overcome when it comes to $/Hp though I wonder about the tuning with Speed Density. Without firsthand experience, it may be possible to build an NA engine with similar idle and manifold vacuum characteristics that the pcm will not have a large tuning curve with besides fuel quantity for a given kPa seen at the intake manifold. Simply put, same power peak and curve but just More of it. Now, that might take some trial and error...and $$ with the goal of stock like driveability... as much as possible. There are many tuners who are losing ground to technology lately. Sure they can get it running and make more power, but it's the complexities like trans tuning and the fact that every system is connected that can throw some unexpected curves that many tuners and owners just end up living with.

IF you can go with a 426 and keep the cylinder wall thick for ring control, with tuning in mind, I may just do that if there is some knowledge base to get a "tame" behaving starting point close to stock behavior. It would be a more unique option. I like the stock 392 in mine. More of the same characteristics would be great...if you can hook it up. :thumbsup:
 

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Would be nice to know who is doing the tuning. It has to be a Diablo or HP Tuners interface though. HP Tuners was the first to crack. HP Tuners cracks the encryption on the PCM and provides the interface for tuning, they don't actual provide tunes.

There are a few shops getting pretty good with the HP Tuners interface and I would, and will, choose a good tuner using HP Tuners over Diablo. I'm just waiting to him to say he's ready. Hint... he used to work for API.
I could be wrong but I think the extra cubes on API's 426 come from increasing the crank from 3.72 to 4.08.

I chose to go with a Maggie on my Scat Pack, when I get the car back I'll drive it for a year or so then do drop in pistons and up the boost. Then if I need more I can stroke it later.

Why wait a year later to drop in forged pistons? I would do all forged internals on a supercharged 392 now..........I've heard too many horror stories of 392's blowing up with stock internals and boost. Just my 2 cents.
how Many horror stories have you heard recently? Their are issues with the 6.4 and boost but I think many Of those were either tune related or too much boost... I asked Luke and he said they've never had a failure.
 

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It wouldn't surprise me if they wouldn't do it, but if I was to try to get any shop to build a Hemi, it would be Tony Bischoff. He's a very intelligent builder of the Engine Masters series of Popular Hot Rodding. Our school competes against him and Jon Kaase every year and we hang with them. The modern Hemi isn't our specialty though.

Usually FI will overcome when it comes to $/Hp though I wonder about the tuning with Speed Density. Without firsthand experience, it may be possible to build an NA engine with similar idle and manifold vacuum characteristics that the pcm will not have a large tuning curve with besides fuel quantity for a given kPa seen at the intake manifold. Simply put, same power peak and curve but just More of it. Now, that might take some trial and error...and $$ with the goal of stock like driveability... as much as possible. There are many tuners who are losing ground to technology lately. Sure they can get it running and make more power, but it's the complexities like trans tuning and the fact that every system is connected that can throw some unexpected curves that many tuners and owners just end up living with.

IF you can go with a 426 and keep the cylinder wall thick for ring control, with tuning in mind, I may just do that if there is some knowledge base to get a "tame" behaving starting point close to stock behavior. It would be a more unique option. I like the stock 392 in mine. More of the same characteristics would be great...if you can hook it up. :thumbsup:

My 426 is an HHP/BES and Josh @ HHP nailed the tune. I don't have the monster numbers of a blower by this is a reliable and drive-able setup. It's actually quite enjoyable to drive and it is an animal when you get on it. All without the maintenance that comes along with FI.

Because it is forged, I could do power adders later if I so desired and it would handle that.

It's near factory enough that my wife can drive it. 6M.
 

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how Many horror stories have you heard recently? Their are issues with the 6.4 and boost but I think many Of those were either tune related or too much boost... I asked Luke and he said they've never had a failure.


Well one guy who races at my drag strip blew a piston in his 392. His engine was destroyed beyond repair after that. He was running 8psi with a Procharger on stock internals. I'm pretty sure Luke stays at 6psi tops on his 392 supercharged builds. He probably also uses a very conservative tune. But anyways, it's your car and you can do whatever you want with it. If I had a brand new 392 and I was going to supercharge it, I'd definitely get the whole thing forged. Hell, I won't even supercharge my 5.7 without forging it first. haha
 

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Was he still using the stock SRV intake manifold? AJ post a thread on another forum awhile back showing that A/F ratio could vary up to 1 full point bank to bank using the SRV manifold...

Problems with the tune plus too much boost is deadly... I would never Run 8lbs on stock internals... No room for error.
 

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My 426 is an HHP/BES and Josh @ HHP nailed the tune. I don't have the monster numbers of a blower by this is a reliable and drive-able setup. It's actually quite enjoyable to drive and it is an animal when you get on it. All without the maintenance that comes along with FI.

Because it is forged, I could do power adders later if I so desired and it would handle that.

It's near factory enough that my wife can drive it. 6M.
That's the ideal setup it sounds like.:thumbsup:
 

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That's the ideal setup it sounds like.:thumbsup:
My 426 is an HHP/BES and Josh @ HHP nailed the tune. I don't have the monster numbers of a blower by this is a reliable and drive-able setup. It's actually quite enjoyable to drive and it is an animal when you get on it. All without the maintenance that comes along with FI.

Because it is forged, I could do power adders later if I so desired and it would handle that.

It's near factory enough that my wife can drive it. 6M.
Newbie question: What would the cost be to do what you describe above, and as compared to a blower/procharger?
 

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My combo has proven to be solid. 2.5yr on the blown stroker and 16,000 miles with zero trouble aint to bad. Still can drive it anywhere to boot. And 20mpg....
FlatTop
 

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I think better mpg using FI over the huge cubes that suck lots of fuel just keeping it running around. My 2c anyway.
FT
 

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Newbie question: What would the cost be to do what you describe above, and as compared to a blower/procharger?

And again to my point. Flattop has a BLOWN FORGED aka forged internals with a blower. The operative here is forged.

You're going to do the forged part if you want reliability with a blower. So just add anywhere from $8k to $20k depending on how you want to do the forced induction ON TOP OF a forged bottom end.

Keep in mind that when you go for that big power you also need to beef up a few other things like axles, diff, clutch / auto trans, fuel system , etc so be prepared to add some $$$ there as well.

With just the stroker it's a good idea to do something with the axles and *maybe* the diff, clutch / auto trans mods, but the stock fuel system will support it. And you can bolt on some power adders later if you so desire.

I got 19mpg [ stock 6.1 I used to get about 21-22 ] cruising along at 82mph for an entire tank measured by mileage and gallons pumped not that goofy on-board computer. Not too bad for all those 426 cubes just loafing along. If I was interested in big mpg I'd be driving a 4 banger :grin2:

All this is simply you're gonna pay to play it's just a matter of how reliable you want it to be. To me unreliable equates to more expensive in the long run. If you're gonna do it, do it right and you'll be happier for a longer time.

Would I ever do the "440" stroker, probably not. The rod angles are too close to the edge with this 3rd gen HEMI. Way too much stroke.
 

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I've seen at least three 6.4s incur damage after running FI. None had forged internals and at least one was running 8lbs (and no idea who tuned any of them - although I'm sure it wasn't any of our supporting vendors). That said, I've also spoken to several people who run 6lbs just fine, but the pistons and rods I saw pulled out of the last 6.4 that ran boost has stuck with me. So if I ever go FI I'm going to go forged at the same time since I drive mine 8k+ miles a year.

I do admit though a 426 just sounds a lot cooler.
 

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if it were my 10k to spend, i would just put forged drop ins in it and then drop a whipple on top of it and make 575-600 at the wheels and be beast.

it's more cost effective to go this route IMO. you could go 440 NA but reliability down the road won't be there and you wouldn't be able to supercharge it unless it was an aluminum block which is way out of the 10k price range. a 426 would be cool but i would just stick with the 392 as it is, forged pistions and blower with like 9 or 10 psi.
 

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Hmmm

My two options would be..

392 Based 426, I would have forged internals and then add Nitrous system for those big runs only.. But a daily 426 sounds awesome.

or

392... Forge it... Then slap a supercharger on it and up the boost.

Decisions Decisions.. Thoughts?
 
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