My brother and I are Hellcat swapping his 71 Demon

[lunytuned]

Hello all, as the title states, we're starting to research this huge process. Car is an original slant 6 car from what we can tell, (fender tag is long gone) and we are installing a Hellcat engine and using an 8hp70. We are going to use the RMS front suspension with Tbar delete for the swap and TTI 2inch primary headers. Car has a Fab 9 diff, Caltracs and a CM 10 point cage already. Hoping to get some questions answered and some guidance from the more experienced members. Thank you!

 

[Ironracer]

Y'all Kick ***! They have a 3rd Gen Swap page here. ALOT of them have been where you are going! Peace Man!

 

[Ironracer]

That's gonna be one Bad ****!

 

[Just Send It]

From a former Pinellas County native, Welcome!

We have a great modern swap forum here. The rabbit hole goes deep. You can get lost for days reading through the posts.

My suggestion would be to get the full plug and play harness to make the wiring a little easier. It's not exactly cheap, but simplifies the process. Also, you may have to modify (or BFH) the tunnel to fit that transmission.

 

[lunytuned]

From a former Pinellas County native, Welcome!

We have a great modern swap forum here. The rabbit hole goes deep. You can get lost for days reading through the posts.

My suggestion would be to get the full plug and play harness to make the wiring a little easier. It's not exactly cheap, but simplifies the process. Also, you may have to modify (or BFH) the tunnel to fit that transmission.

Thank you and wow, you're not kidding about the rabbit hole. From my limited time looking, it's already deep lol! I am honestly not sure what ECU he wants to use. I like the TerminatorX and I'm sure he's going to use German sound for the trans control. Apparently, someone makes a tunnel kit with directions for around $1200. And yes, this is not a cheap process regardless of which direction you go.

 

[MopaR&D]

Welcome, sweet ride and sweet plans!

Just thinking out loud, since the car is so light compared to what those Hellcats normally come in you might be better off with an older transmission with less speeds. Then again the 8HP70 already has the strength to handle the power and pretty tall overdrive gears if you want to go on some long-distance drives.

 

[lunytuned]

Welcome, sweet ride and sweet plans!

Just thinking out loud, since the car is so light compared to what those Hellcats normally come in you might be better off with an older transmission with less speeds. Then again the 8HP70 already has the strength to handle the power and pretty tall overdrive gears if you want to go on some long-distance drives.

I originally wanted him to use a 46RH and thought that was the way he was going to go. But, he's a transmission guy at Dodge and from his perspective, couldn't see using an older, less efficient trans for the build. I figured it would be cheaper to do the 46RH but after you spend 5 or 6k on parts from Cope transmissions to hold that kind of power, then another grand or so for a good converter, it just can't compare with what he was able to score on the 8spd.
I really want to do drag and drive events with it, we have a really cool one down here in Florida so yes, the over drives are needed.

 

[MopaR&D]

I originally wanted him to use a 46RH and thought that was the way he was going to go. But, he's a transmission guy at Dodge and from his perspective, couldn't see using an older, less efficient trans for the build. I figured it would be cheaper to do the 46RH but after you spend 5 or 6k on parts from Cope transmissions to hold that kind of power, then another grand or so for a good converter, it just can't compare with what he was able to score on the 8spd.
I really want to do drag and drive events with it, we have a really cool one down here in Florida so yes, the over drives are needed.

That definitely makes more sense then, sounds like he knows what he's doing. You would definitely need to build up a 46RH to handle that power and they are not very efficient. I have a coworker who used to work in manufacturing at a ZF plant, he had good things to say about how that company makes its products. Only downside is how physically large those transmissions are for our old Mopars but if he doesn't mind cutting up the trans tunnel it's a no-brainer.

 

[Car Nut]

 

[tinman2]

Did you check out HDK K-member and swap parts? Very nice.
@HemiDenny

 

[COOL WHIPPS LLC]

Hello all, as the title states, we're starting to research this huge process. Car is an original slant 6 car from what we can tell, (fender tag is long gone) and we are installing a Hellcat engine and using an 8hp70. We are going to use the RMS front suspension with Tbar delete for the swap and TTI 2inch primary headers. Car has a Fab 9 diff, Caltracs and a CM 10 point cage already. Hoping to get some questions answered and some guidance from the more experienced members. Thank you!

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Welcome to the site! I'm also a relative new member planning to do the same swap to a '75 Duster sans the 8HP70 and planning to bore/stroke a 5.7, add 6.1 heads, topped off w/the Hellcat S/C. You're starting with a much better car because it already has a nice cage. I'm starting w/ a relatively clean shell, minus the rotted LH frame rail. Rear will be a Scott's 4-link attached to an narrowed 8-3/4.