345 vs. 392

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T Jones

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I've watched a lot of videos and read a lot comments on building 5.7s to get the power of a 392. It never made sense to me to sink tons of money into a 5.7 just to get the output, (or a little better), that, i.e., a stock R/T 392 would make. Am I wrong? Any thoughts?
 

Brandon-w

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5.7 VS 6.4 is about 90 hp difference. But the torque feels way different to me.

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tidefan1967

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From what I've read and seen the 5.7 is actually a better base to start from although you got a lot of work to do just to get that initial 90 HP back. Not sure about the truck version of the 6.4 tho.
 
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T Jones

T Jones

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From what I've read and seen the 5.7 is actually a better base to start from although you got a lot of work to do just to get that initial 90 HP back. Not sure about the truck version of the 6.4 tho.
I think the 392 truck version, from what I read, is like 425 hp with 417 ft pounds of torque. Although that may have changed with the newer RAMs.
 
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T Jones

T Jones

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5.7 VS 6.4 is about 90 hp difference. But the torque feels way different to me.

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The torque in R/T versions of the 6.4 is like, 475 ft lbs.? Our 5.7s have 395 hp with 410 ft lbs of torque by comparison.
 

RedSRT4Me

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I've watched a lot of videos and read a lot comments on building 5.7s to get the power of a 392. It never made sense to me to sink tons of money into a 5.7 just to get the output, (or a little better), that, i.e., a stock R/T 392 would make. Am I wrong? Any thoughts?

How much can you score a 6.4 engine for?
 

Wild one

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How much can you score a 6.4 engine for?

Brand new complete 6.4 SRT is probably right around 7,000/7500 Stateside,they're roughly 11,000 Canuck with a good deal at a dealer. The 6.4 SRT is rated at 485hp and 470 lb-ft,but compared to the 5.7's 410 lb-ft,it seems like alot more then just a 60 lb-ft differance. The cars after 2017 also use the BGE block,same block as the HD trucks have used since 2014,and they make a hell'va basis for building a big cube stroker.You can take them all the way out to 454 cubes if you have deep enough pockets,but the 2 most common sizes are 422 and 426.
 

savage_46

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I've said it many times to whoever has brought it up. 5.7 to 6.4 is a night & day difference. Can a 5.7 be built to out perform a 6.4? Of course, but all those same things done to a 5.7 can be done to a 6.4. If you can swing it, i say do a swap. Then add on to it as time/money allow. Personally, I'm aiming for FBO 6.4 & haven't decided if this truck is getting a whipple or not.
 

RedSRT4Me

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Brand new complete 6.4 SRT is probably right around 7,000/7500 Stateside,they're roughly 11,000 Canuck with a good deal at a dealer. The 6.4 SRT is rated at 485hp and 470 lb-ft,but compared to the 5.7's 410 lb-ft,it seems like alot more then just a 60 lb-ft differance. The cars after 2017 also use the BGE block,same block as the HD trucks have used since 2014,and they make a hell'va basis for building a big cube stroker.You can take them all the way out to 454 cubes if you have deep enough pockets,but the 2 most common sizes are 422 and 426.

Right so depending on the budget the 6.4 engine might not even be in the cards. :oops:
 

Tray Burge

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There's more to factor into that also, it's not just the engine.
Personally, I'd just rather do the upgrades on the truck I have now because of the other mods, the body style it is and the way I have it set-up. That's just me though.
You can never have enough and there's somebody else that always has more, so when are you happy?
For me, 400HP at the rear is more than plenty, Hell what I have now is more than I can reasonably use on the streets?
I don't race or street race, just as long as it sounds great and has great off-the-line torque, I'm happy.
I'm old though and I've learned the blessings of being content too. lol
 

Jose Zambrano

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One other thing why most people use the 5.7 instead of the 6.4 is because the 5.7 does better with boost applications than the 6.4 engine.
 

Wild one

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One other thing why most people use the 5.7 instead of the 6.4 is because the 5.7 does better with boost applications than the 6.4 engine.

You gotta build the 5.7 for boost to,otherwise it's a ticking time bomb.You put the same quality of parts into the 6.4 as you need to put into the 5.7 and you'll have comparable engine life ,but with 47 more cubes to play with.
 

Wild one

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Right so depending on the budget the 6.4 engine might not even be in the cards. :oops:

Tough to build a reliable 5.7 to 485 horse for the cost of the 6.4,that comes with a 3 year warrenty. Buy a manual transmission SRT 6.4 and it's already MDS deleted with a pretty decent cam
 

RedSRT4Me

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Tough to build a reliable 5.7 to 485 horse for the cost of the 6.4,that comes with a 3 year warrenty. Buy a manual transmission SRT 6.4 and it's already MDS deleted with a pretty decent cam

Tough to build anything if the OP doesn't have 7000 :33:

Think about mail ordering an engine and you want warranty work. You gonna mail it back? Who's gone through that process? Sounds like a major headache unless you have someone local to provide the parts.
 

Wild one

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Tough to build anything if the OP doesn't have 7000 :33:

Think about mail ordering an engine and you want warranty work. You gonna mail it back? Who's gone through that process? Sounds like a major headache unless you have someone local to provide the parts.

Go through your local dealer,takes care of any issue with mail order.I've yet to see a dealer who won't price match the price from another dealer or the online Mopar dealers.All you gotta do is ask them,and odds are they'll match the price.
When i got Brandon-W his engine,i used my connections at my local dealer,and they beat the online price
 

RedSRT4Me

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Go through your local dealer,takes care of any issue with mail order.I've yet to see a dealer who won't price match the price from another dealer or the online Mopar dealers.All you gotta do is ask them,and odds are they'll match the price.
When i got Brandon-W his engine,i used my connections at my local dealer,and they beat the online price

Nice. And back to my question to the OP on what kind of budget he has to work with.
 

stc315

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My 2014 has over 230,000 miles on it (rebuilt top end with MDS delete and Hellcat valvetrain hardware and lifters at 130k miles) and I've been contemplating getting a new truck or replacing the 5.7 with a 6.4. It's nice not having a payment but everything else is getting old on it too. I'll probably have another 45,000 miles on it before I'm ready to make the change next March. Still running the rest of the original powertrain too with nothing done to it but fluid changes. I may even change brands since the only way to get a 6.4 in a Ram is to go to 3/4 ton. I've been super happy with Ram (this is my second, my first was a 2005 5.7), but I want a little more power and want to keep the smoother half ton ride quality.
 

Wild one

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Nice. And back to my question to the OP on what kind of budget he has to work with.

I don't think that was what he was asking,if you read his original post.I think he was inquiring why guys would build a 5.7 instead of a 6.4
 

ramffml

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Go through your local dealer,takes care of any issue with mail order.I've yet to see a dealer who won't price match the price from another dealer or the online Mopar dealers.All you gotta do is ask them,and odds are they'll match the price.
When i got Brandon-W his engine,i used my connections at my local dealer,and they beat the online price

So as a fellow Canuck; was that $11,000 for a 2500 6.4 or the 485hp 6.4? And I take it that wasn't installed yet either?
 
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