It is quite literally more expensive to put a HC engine into a non-Hellcat than it is to spend 50k or so on a used Hellcat.
Why? I'll try and keep this brief, as I've been involved in 2 of these:
- Hellcat engine: (Crate = $15,000-$18,000, OEM new = $20,100 for a 717hp stock new factory crate engine...comes with a warranty)
- Need new 8HP90 transmission (or a refurbed one... $7-12k)
- Driveshaft upgrade ($1,500)
- Likely axle half shafts and a rear diff ($3k)
- New PCM and TCM ($1,600)
- New dash and UConnect screen ($2,000)
- ALL THE WIRING. ALL OF IT. 100% ALL THE WIRING. Take the old stuff out, rewire the entire damn car. Otherwise, when you go for the first start, it's going to throw 300-400 codes. I'm not kidding. On the first car we did, we chased all the codes and spent literally 3 months swapping out solenoids, relays, fuses, fuseable links, etc. On the 2nd car, we replaced all the major wiring harnesses and it took us from 380 codes down to 84
- Front suspension components need beefed up for the heavier powertrain ($3,000-$5,000)
- New wheels and tires
- New fuel pumps
I'm likely missing a few of the key items, as it's been a few years. But the other side of this is that the work will take months. Your labor bill will likely exceed the parts cost by a factor of 2. The labor will be exceptionally expensive if you put a delivery condition on them that demands a no CEL guarantee. If you don't do that, you may very well get a swap, but it'll end up with the aforementioned dozens and dozens and dozens of codes. That's because the way the PCM works, it polls everything from the rear camera to the window motors. If it gets a voltage irregularity, it prevents the fuel pumps from turning on. Bypassing it just causes another error to pop up that prevents the ignition from sending spark, and so on, and so on. On the first car we did in 2015, it took us and a team we flew in from Diablosport 3 weeks just to figure out why the car wouldn't start. Turns out the rear camera module was tripping the voltage code, which couldn't be cleared because the PCM was looking for a different camera that ran on a different power setting. So, we had to swap the spoiler and the camera to get the fuel pump to fire up.
Including the price of the owner's car, his out the door price including parts and labor on the Hellcat swap was just about $90,000. This was back when a new, well equipped Hellcat was 65 grand. Today, this is more of a fine science for shops who know how to do it, so you can generally add $40,000 and that will upgrade a SP to a HC spec.
Keep in mind that to do the engine swap, you have to pull the entire interior to do the wiring harness swap. It's actually considerably cheaper to HC power a car that didn't have a Gen 3 Hemi in it than it is to transplant a 6.2L into a Challenger/Charger where a 5.7L once was. That way you can just use Dodge's Hemi kit and that's all you need. But, you can't use that on a modern Challenger/Charger because nothing in the car will work.
And, as always, I'll go ahead and mention that it's against Federal law to perform the swap, so lots of shops are turning down these builds due to increased pressure from the EPA. It's a 25k fine if they get caught doing it. If you get caught driving an illegally swapped engine, it's $6,000 to you, mandatory vehicle impound, and you'll be court ordered to revert it back to OEM or pay to have the vehicle disposed of.
Long story short, it's ludicrously expensive... and when you're done, it's illegal and no warranty. Insurance companies will give you serious grief about insuring it, unless you lie about it. If you ever have a claim though, it's a great way to get denied and have your policy canceled if you did in fact fail to disclose the swap.