Opinions please- new hemi or 408?

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racerjoe

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I proposed this question in my build thread but thought this section may be appropriate as well.
I bought a complete 2006 5.7 hemi out of a cop car for crazy good price. I wasn't even in the market for it but couldn't pass it up. Now do I reuse my built 408 or use the hemi? I plan to use the car as a reliable driver. I know the 408 will have more power and could be just as reliable.
I figured most guys on under this thread are pro hemi, but it would be nice to hear some opinions of the guys who have done it. I'm torn because I love the torque my 408 has, but the hemi is, well, it's a hemi. Opinions are greatly appreciated!
 
Depends how much more work your willing to do, I'm guessing you have everything to drop the 408/ trans / wiring etc in it in a day. Not sure what you have, will need, fabricate, etc to get the hemi/ with trans and wiring all sorted out.
 
I agree^^. It depends on how close your car is to being drivable. If you could drop your 408 and drive it this year do that, while collecting parts for a hemi swap. If you have the car down to the bones, do the hemi, as long as you like challenges!
 
All honesty it's a bunch easier to deal with a 408, in installation and troubleshooting.


And to be politically correct it's not a hemi-sphere, really, it's a pentroof, which doesn't sound as sexy.



If your really all about the 'hemi' name, just slap a sticker on it.

10/10 people won't know the difference when you pass them.
 
The car is down to the bones right now. I'm also rewiring the entire car and converting the 408 to EFI. I already have the engine controller which will work on the 5.7. The car was already setup for a tremec and I would intend to use that too. I don't give a **** about the name hemi- more interested in the modern motor. I'm just wondering if it's worth the BS to make it fit
 
I'm still building mine, so I can't offer experience, yet. I did check out your build, very nice Duster you've got there. A warmed over 5.7 with eagle heads or a 6.1 with ported heads, a mild camshaft .219/.223 @ .050 with headers should put down about 420-440 HP @ the wheels, run without issue on pump gas and manage 20MPG on a cruise. In other words, it should make almost the same power as a warmed over 408 LA. My ported 6.1 heads flow between 340-348cfm from .550-.600 lift.

If you go with the 5.7, mock it up with the transmission and headers as it's a pretty tight fit. Good luck and I look forward to following your build.
 
My brother runs a 408 and its a hell of a motor. But the potential these Hemi motors have is amazing. If you put the same build effort into a hemi as the 408, the Hemi will outpower it. Just good heads and a cam will get you 500hp easy. Getting the Hemi running will be more expensive than the 408, but not horribly since you were planning on EFI anyway. Quite the learning curve when it comes to installs. What works, what doesnt.

BTW- I was a diehard BB guy until I saw how the Hemis were responding to mods. Sold it all and made the move to the gen 3 hemi.
 
that modern Hemi is a nice piece in a lot of respects
...but it's an odd looking thing.
 
that modern Hemi is a nice piece in a lot of respects
...but it's an odd looking thing.
 
Use the pilot bearing from a magnum era truck (96 ram 5.9 etc) it fits in the torque converter register.
 
Agreed it is an odd looking engine. Especially when this looks so awesome!
 

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I could have gone the Hemi route, but wanted power steering and didn't want to swap out the entire front suspension with a pricey aftermarket unit.

I ended up with a 5.9 Magnum based 408 ported-Eddie-headed, roller-cammed stroker motor complete with OBD II EFI, a 3000 rpm lock-up torque converter and a non-computer controlled 4 speed overdrive automatic hooked to 3.91 geared 8 3/4 rear end.

It's a Doctor Jekyl Mr Hyde type of ride now. Great mileage, very quick AND fast....too fast for the chassis actually. ( 1968 convertible Barracuda)

Do I wish I would have spent more money for the front suspension and the Hemi? Nope!
 

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I'm kind of in the same bout as you but I have my slant 6 right now. I want the car to be a lot more reliable and get god gas mileage while cruising and ended up stumbling across a trans/ecu/harness/fuse box/ torque converter/driveshaft out of a 05 Rumblebee for $350 so it gets me most of the things I need for the swap at a very cheap price. So I'm heading in the 5.7L direction mainly because that's the deal I came across and it seems like every Dart I run into at shows has the 318/360 in it and id rather be a little bit different then everyone else. If I had found the same kind of deal on a 408 with the extras I might have gone a different route. But I'm excited to start my build soon.
 
You wish!! Haters hardly have any nuerons! Maybe when you're asleep you know more than me. Not!! Racist loser!!
 
Wow, cool solution. Which steering box is that? Beautiful headers too.

Thanks, Borgeson first design box, New one is even smaller. TTI has the credit for headers. I made my own mounts because of /6 k member and wanted engine lower and more towards d-side.
 
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