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How does the Hemi compare?

wrenchinrandy

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Good evening everyone. I’m new to the website. If this question has already been asked, I apologize. I did do a little bit of searching, and didn’t see my question directly discussed. That question is for those running the new Hemi. How does it compare to the vintage engines in terms of daily driver type use. I have a 2020 Challenger WBSC and love it. It is fast when I want it to be, idles politely, doesn’t get hot, and gets surprisingly good fuel economy. My ‘67 Charger has been a big block of various sizes all of its life. It has been converted to EFI, and has a Viper T56 behind it. While for the most part, I’m content with the big block, it’s has always been a leaky pig, and due to several issues, it never ran to it’s potential. So when the 451 developed a terminal problem, I find myself on the fence for a replacement big block, or changing to a new Hemi. I would like to know how well those that made the change, like it. I know there are pitfalls, unforeseen costs, and other headaches. Do the new engines work so well that none of that matters? Especially in comparison to a good running big or small block. Thanks!
 
Welcome to the site and it's a good idea to introduce yourself in the Welcome Wagon....and I'm guessing the new engines are working well because of all the electronics on them.....?
 
The new Hemi's can hold their own with with any of the old ones when it comes to apples to apples performance. Tons of reasons as to why or why not when it comes to swapping one in an old car but it pretty much boils down to a guys personal desire. While they don't leak as much as the older ones they are much more expensive to swap in plus the older ones can be made to be leak free as well. I swapped in a 6.1 in my 68 Charger for a few reasons.
1. They run good on the dog piss gas available these days.
2. They are more fuel efficient.
3. I wanted the 5 speed automatic transmission for performance and mileage.
4. I'm not into the numbers matching game but wanted to keep an all Mopar drive train.
That said, it is totally up to you what you do with your car but being a leaker is not a good enough reason IMO. As for me, I am very happy with the way my car turned out. It was a nightmare from hell for a while but it was in the early stages of these swaps when I did mine years ago. Now there is tons of leadership and aftermarket parts to make it happen. It gets easier but not cheaper.
 
It seems a well built shortblock could cure your ills. That being said if you want to go that route jump in.
 
The appeal of a 3G Hemi is strong for good reason.
I have one in the 2007 Ram....it is over 399,000 miles.

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I'm not a purist for these cars. If something comes along that has clear advantages, I give it consideration. My red car has a few modern changes like 4 wheel disc brakes and a 5 speed manual transmission but it is still has classic 440 based engine.
Jigsaw though....

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This is a non pedigree car with no special history. It is a clean slate so going with something modern is very tempting.
I'm thinking a 5.7 with a 4.0 crank, Eagle heads, 6.1 or equivalent intake, full length headers and a A500 or A518 4 speed automatic. I'd have 420+ HP, 25 mpg and freeway at 75 doing 1600 rpms.
I'd miss the rumble of the big cammed classic engines though.
 
I suspect you already know the answer to your question and came here for validation, not that there is anything wrong with that but from the sounds of it you are not new to the car world and you already have an old and new example to compare.

All that said, I agree that there are reasons for and against both courses of action and ultimately its a personal choice. I have a 440 with EFI 6 pack in my 70 Challenger RT, a 416 stroker with EFI 6 pack in my 73 Cuda but I am putting a 5.7 into my 71 Charger but will put a 66 426 Hemi into my 70 Roadrunner but a 5.7 into my 68 Cuda... Different choices for different circumstances.

I will say that if you actually want to drive the car then go G3 Hemi for all the reasons you already are aware of.
 
I did the Gen-3 change to my 70 `cuda. I would never consider putting an old engine back in it's place. It's so much lighter, faster, and quicker than any old-school engine would have been...plus gets 20-24 MPG on the highway at 80 mph. I'm running it with a NAG trans, and all the new-car electronics. Some editing to the computer eliminates the "nanny" stuff and fools other parts to appear working.
My new 300C has the 8-speed and feels very quick. However, it has all the "nanny" stuff and doo-dads. It needs the 8-speed, due to the weight. I still love it. I just did a 700 mile trip with it at 80-83mph, and it got about 22mpg.
 
Thanks for the responses everyone. Ed, Ruffcut is correct, WBSC is widebody Scat Pack. 70Chall440, I appreciate your insights, but honestly I don’t have a vision or even inkling of where I am headed. Hence the post. You are correct, I’m not new to this. I’ve had mine for 33 years, lol. I’m also completely comfortable with the newer technology. One of the changes I do feel pretty sure about is changing to an 8HP transmission. The T56 has been a disappointment due to shift quality. However now that the tunnel has already been modified, pretty much anything will fit. That will of course require a controller, but as I’ve already wired in a Holley Dominator running the big block, I feel like it’s an obtainable idea. What remains is what will turn that transmission. I have only known a big block in the Charger, but am very impressed with what the Challenger can do. The car is very much a driver. Besides multiple Power Tours, it’s also been to Montana several years ago. That use can’t change, or else I will lose interest in the car. For those that mentioned economy, the six speed allowed the big block to get 18MPG at 75, and I feel that it would have been capable of more had I identified the issue with injectors before the engine let go. I was just trying to get a perspective from those that have already made the swap. Thanks to everyone for the feedback.
 
Thanks for the responses everyone. Ed, Ruffcut is correct, WBSC is widebody Scat Pack. 70Chall440, I appreciate your insights, but honestly I don’t have a vision or even inkling of where I am headed. Hence the post. You are correct, I’m not new to this. I’ve had mine for 33 years, lol. I’m also completely comfortable with the newer technology. One of the changes I do feel pretty sure about is changing to an 8HP transmission. The T56 has been a disappointment due to shift quality. However now that the tunnel has already been modified, pretty much anything will fit. That will of course require a controller, but as I’ve already wired in a Holley Dominator running the big block, I feel like it’s an obtainable idea. What remains is what will turn that transmission. I have only known a big block in the Charger, but am very impressed with what the Challenger can do. The car is very much a driver. Besides multiple Power Tours, it’s also been to Montana several years ago. That use can’t change, or else I will lose interest in the car. For those that mentioned economy, the six speed allowed the big block to get 18MPG at 75, and I feel that it would have been capable of more had I identified the issue with injectors before the engine let go. I was just trying to get a perspective from those that have already made the swap. Thanks to everyone for the feedback.
I'd go G3 in a heartbeat just saying.
 
Just get in and go on a new Hemi car.
No pumping the pedal just right. Hoping the choke sets. Hoping the oil pressure comes up and stays. Listen to the lifters rattle. Eyes are watering from the rich mixture. And on and on for the old ones.
 
Just get in and go on a new Hemi car.
No pumping the pedal just right. Hoping the choke sets. Hoping the oil pressure comes up and stays. Listen to the lifters rattle. Eyes are watering from the rich mixture. And on and on for the old ones.
Well, maybe if you can't tune a car for ****...
 
Just get in and go on a new Hemi car.
No pumping the pedal just right. Hoping the choke sets. Hoping the oil pressure comes up and stays. Listen to the lifters rattle. Eyes are watering from the rich mixture. And on and on for the old ones.
Well, maybe if you can't tune a car for ****...
I've experienced a few cars like that over the years but they usually came from a previous owner. It's unreal at how so many claimed to know how to work on cars but were only posers. Yeah, the new cars can be really nice but when something is wrong in the electrical system, they are usually nightmares!!
 
Not many members here can remember when these Hemi cars were new.
Very few owners of factory, multi carb Gen ll Hemi cars could or would take the time to stay on top of the tune of these cars.
They were not very user friendly. One of the reasons many opted for the 440 instead of the Hemi back then.
Not like keeping a 318 or 383 car car running good.
 
Come on, man…..You didn’t read the opening post. The OP is asking about the NEW generation of Hemi engines.
I agree that the 440 was a viable option for their lacking the ability and desire to tune their carburetors.
 
I’m currently Gen3 swapping my 65 Satellite after the 440 ate a cam after 1000 miles don’t know what to expect I am sticking with a carb set up to keep it semi old school and I’m using an engine plate instead of aftermarket mounts.

Opinion here but… I think the wedge stuff is gonna be harder to get and the quality not as good, and the new stuff is most often able to be bought off the shelf.

6.1 block stroked to 426 Molnar crank and rods Mahle pistons

Eagle heads ported

10.8.1 compression

Cam is 239/251 583/583. 112+2 centerline

Prefix intake and a 950 carb

Msd ignition

Assault water pump

ATI balancer

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5.7 Hemi I just removed a stroker, with EFI. A 451 with lots of good parts. Parts that could of course be used on another B engine. Honestly, that would be the easiest as everything is already there. The 451 was not in a great state of tune (I eventually found that I was fighting 8 bad injectors), but even so, it idled well, never ran hot, and got reasonable economy. Early in the build it made good power, but for most of its life, I was chasing gremlins. The thought of a Hemi sounds appealing. The hassle of putting it in is as distasteful as building another big block. That is why I wanted some perspective. I want to know that the Hemi is better all around before I bother with the hassle of a swap.
 
I own both. A 2012 Challenger R/T Classic with a 5.7L Hemi for my daily fair weather driver. And, also 3 other Gen II Hemi's. I have a 528" Hemi in my 70' Challenger currently. I like them both for different reasons. However, no matter what anyone says, as impressive as the Gen III Hemi's are with today's technology. They do not come close to comparing to a Gen II Hemi.

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