This post will be a little long. My Brother has a 2020 Challenger 1320. It's almost completely stock. It' has bigger injectors, smaller crank pulley and tuned for E85. It weighs 4330 lbs with him in it. In good air it has been 11.00 in the 1/4 mile. That comes up to 638 hp on the Wallace power calculator. Now to my point. How much HP can the 6.4 Hemi block take? I'm thinking with some compression, a solid roller cam and a good port job it'll make 700 plus hp. I know that the rods are the weak point. What I'd like to know is will the Hemi mate to my SBM trans and converter. What is the high point that the block and crank will take? I'm thinking about selling my SBM stuff and going Gen III when my current Bloomer headed engine is due for replacement.
Gen III Hemi
- Thread starter tvt59
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The trans will bolt right up. Just need a flexplate from ATI or Bouchillon. The car hemi cranks have a ring pressed into the crank register that has to be removed. Weld a nut or whatever to it, then use a slide hammer. Block will easily handle anything N/A. They'll still handle a considerable amount boosted. 6.4 all have forged cranks, so you're good there. I don't know the limits of the stock floating rods, but, I'd guess anything after 7000 RPM is a gamble. No real need to go solid roller, unless you're looking to spend a metric **** ton on valvetrain. The stock rockers and good juice lifters will live at that 7000 mark. I'm not sure if anyone makes a drop in solid roller lifter. Guys have bushed, keyed for different pieces. The cylinder heads flow like a mother. If you had that engine in car that was a 1,000 pounds lighter, easily be in the tens. And the engine wouldn't really work too hard.
RockinRobin
Well-Known Member
My 5.7 block has been running at 700 hp for a long time, but the crank and rods are not stock and the pistons are 13.5 :1. As to rpm I shift 1st to 2nd at 7200 all the time and my Rev limiter is set at 7400 which I hit occasionally when I miss the shift. I've been told that stock shafts and rockers are good to 7500 and I've had no valvetrain issues revving that high since 2014. I have aftermarket cam lifters and springs. The aluminum heads flow great.
DionR
Well-Known Member
I know the OEM 6.4 BGE blocks have been built to 1000+ hp, SC of course. The BGE blocks are the truck 6.4 and all 6.4's after 2017 (I think) and have BGE cast into the rear of the block.
Not sure on the pre-BGE 6.4 block, but I kind of doubt someone could find the limit of the block without boost.
The Hellcat stuff after a certain year were BGE blocks too. Same bore, different stroke. I want to say after 2015 or so, the trucks, SRT, and Hellcat were all BGE.
Hard to argue with what you have. I love a good small block.
bobtile
Well-Known Member
My 6.4 based NA 454 on the engine run stand.
Heading into my 67 Barracuda shortly.
Heading into my 67 Barracuda shortly.
Is that the latest Mopar drag pak intake? The little we can see looks awesome!
bobtile
Well-Known Member
It's a tall boy...
Such “fugly” engines. Lol
Yep. That's the newer drag pak intake. The runners run higher up into the plenum.
MopaR&D
Nerd Member
I don't think that calculator is right. What's his trap speed? Challenger 1320 is just a 6.4 Scat Pack with all the drag racing extras from the Demon, all SRT 6.4s are factory rated 475-485 HP net at the crank. I can't see how an underdrive crank pulley and E85 conversion would gain ~150 HP. Big reason they can run such quick ETs is the gear reduction and lightning-quick shifts from the 8-speed trans.
With that said, a big cam, long tube headers into cat-less exhaust and optimized non-emissions tune will have a 6.4L pushing 600 HP at the crank.
RockinRobin
Well-Known Member
My stroked out 5.7 with headers, big cam, 18" of exhaust pipe after headers and 13.5:1 compression is making around 700hp at the crank, so a 6.4 should easily make 600hp.
BTW I have the same intake.
MopaR&D
Nerd Member
Those DA values are pretty crazy, I guess that explains a lot of why his HP is so much higher. I tried a few other online calculators using that weight and trap speed and it still comes out to over 600 HP at the tires. Wild.
I watched a video last night of a guy driving around a '70 Duster with a basically stock 6.4 and 6-speed swapped in, he has to run drag radials on the street just so it won't spin the tires through the first 3 gears.
I also know a guy locally with a '72 Cuda who swapped a stock Hellcat engine back out for a healthy stroker SBM because it spun the tires so bad, he almost wrecked it on the freeway when he hit the gas and it did a 180, at 70 mph...
I watched a video last night of a guy driving around a '70 Duster with a basically stock 6.4 and 6-speed swapped in, he has to run drag radials on the street just so it won't spin the tires through the first 3 gears.
I also know a guy locally with a '72 Cuda who swapped a stock Hellcat engine back out for a healthy stroker SBM because it spun the tires so bad, he almost wrecked it on the freeway when he hit the gas and it did a 180, at 70 mph...
DionR
Well-Known Member
Sounds like a video from member @CurtDawg510 on here
Yikes! I have daydreamed about stepping up to an HC in my '73 Duster after I have grown tired of the cammed 5.7 I am going to put in it. Not ready to give up on that but something to keep in mind.
He wasn't running 15" BFG's on it was he?
It sure would be cool to figure out how to retrofit traction control when swapping in a motor like that. I know in my lowly 5.7 Challenger TC might have saved me twice when the rear end suddenly stepped out on me, can't imagine what almost twice the HP and 800# less will be like.
Hotwire Auto's NAG1 kit uses the original ABS module to feed the TCM (among other things), and I am hoping to do something similar to feed a speed signal to the PCM so (maybe) I can get the factory CC working. Maybe by adding the other missing modules, perhaps TC could be added. In my mind the biggest hurdle after the wheel speed sensors is the steering wheel angle sensor. At that point, might be able to just plumb the ABS pump into the system and even have functioning ABS.
As far as I know my brother has the second quickest and fastest stock 1320 in the country there is a guy who has gone 10.95 in Texas but his car is hulled out nothing but a steering wheel and a driver's seat in it. My brother has light weight wheels and tires, bigger injectors, E85 tune, cold air box and a smaller crank pulley.
MopaR&D
Nerd Member
Sounds like a video from member @CurtDawg510 on here
Yikes! I have daydreamed about stepping up to an HC in my '73 Duster after I have grown tired of the cammed 5.7 I am going to put in it. Not ready to give up on that but something to keep in mind.
He wasn't running 15" BFG's on it was he?
It sure would be cool to figure out how to retrofit traction control when swapping in a motor like that. I know in my lowly 5.7 Challenger TC might have saved me twice when the rear end suddenly stepped out on me, can't imagine what almost twice the HP and 800# less will be like.
Hotwire Auto's NAG1 kit uses the original ABS module to feed the TCM (among other things), and I am hoping to do something similar to feed a speed signal to the PCM so (maybe) I can get the factory CC working. Maybe by adding the other missing modules, perhaps TC could be added. In my mind the biggest hurdle after the wheel speed sensors is the steering wheel angle sensor. At that point, might be able to just plumb the ABS pump into the system and even have functioning ABS.
I think you're right, the car in his avatar looks like the exact one!
I don't think they were BFG's but any kind of street tire won't stand a chance. I think his biggest issue was gearing and pedal tuning, iirc he had a 727 with 3.55s. Said he had a really hard time being able to press the gas pedal lightly enough to not break the tires loose from a stop lol.
I don't see myself wanting that level of power unless I'm racing tbh. The 450 HP 360 in my Duster now has it running mid-12s and I'd rather work on dialing in the handling and getting seat time at some track days and HPDE events. I'll swap a 6.4 Hemi into something eventually but I don't think it'll be this car unless I really step up the chassis upgrades to be able to handle the power on a road course.
DionR
Well-Known Member
I'm hoping my 5.7 with shorty headers, 6.4 intake and 6.4 cam get's close to that 450 number. But not shooting for any certain number, and I expect to be more than happy with whatever I get for a good long time. But fun to dream, and I sure like the look of the HC blower.
MopaR&D
Nerd Member
I currently have a 2014 5.7 I've been holding onto for years and had similar plans for it. I need some money though so I'll be putting it up for sale soon as I have no idea when I'll have a car to put it in and the money for all the swap parts. So when the time comes for me to be ready to do a G3 swap I'll get a 6.4 and run that just because it's so much more "optimized" in my mind. However after feeling what 450 HP is like in an A-body I'm not in a hurry to have a bunch more lol, it'll probably be a B-body I swap it in tbh.
Blowers do have a definite cool factor, some day I want to swap a supercharged GM 3800 V6 into a RWD car or Jeep after having driven one for years in my DD 2000 Park Avenue Ultra.
9secRR
Well-Known Member
The 440” W7 engine will make way more then 700 hp I mean way more. If you have all parts to build it, there is no way I wouldn’t build it.
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