318/8 Speed Swap

-
Tripped over a comment on a Challenger forum that some people get over-rev codes with a 3.90 rear gear and an A8 because it can't shift fast enough in the lower gears. Just an FYI, doesn't mean everyone that does that has an issue, but sounds like some do.



The Challenger 245/45R20 is about 28.7" tall so you would be shorter with either tire. So your 2.76 would be like running a 2.83 or 2.97 in a Challenger, depending on which tire.

BTW, the 845RE (A8) V6 Challengers got a 2.62 with the performance option being a 3.08. R/T's and Scat Packs Challengers got a 3.08 or 3.09 depending on if the axle was open or had a limited slip. Hellcat's only come with a 2.62 rear gear, no 3.0x option.
I have a factory 3.91 rear end in my 2021 Ram. 2100 rpm at like 75 mph.
 
Last edited:
Managed to get my mount system ordered I went all Hooker Blackheart may have to modify where it mounts but this gives me a good solid base and replaces the huge upper cross member hoop.

Bhs572/574/578

IMG20240317193834.jpg


IMG20240317193642.jpg
 
Once I have the Dart driving down the road I will have a list of parts used and prices. This is a cheaper option the ZF than a brand new TKX or auto from SST this is not cheaper than say a used A833. About the same as four speed used redone. But if you go Brewers which I would have its more for all new or like new. I had like 6 quotes for pricing I felt the ZF gave me the best bang per buck, also as a veteran from my hips are bad. Army PT did me in! A stick would be fun for a short time and painful to use the clutch.
 
Managed to get my mount system ordered I went all Hooker Blackheart may have to modify where it mounts but this gives me a good solid base and replaces the huge upper cross member hoop.

Bhs572/574/578
I'm eagerly awaiting your progress! Just looked at JVX's website and couldn't find the LA to 8sp adapters. Could you tell me what's the part number on that flex plate and any other details about it specifically?
 
I called JVX the other day to talk about the conversion kit. The gentleman there said the flexplate comes neutral balance but that they could do any balance that you wanted (ie. LA 360 or Magnum 360) for an additional $80. I forgot to ask about the converter snout adapter, I think there are two diameters for the hemi 8HP converters.
 
I need to start thinking about a drive shaft plan. CV joint style 2020 Challenger RT style then needs a slip yoke, then will need a standard 1310 U joint on a 8 1/4 rear end. I ordered my shifter today not cheap the Challenger 8HP shifter and the knob itself 550 from Sound German Automotive. I may go to Tulsa as I'm told that Driveshaft inc does excellent work. If I get that I will have in theory all I need to complete the swap. In about tapped out on spending money I will be pissed if I hate this lol!

So far 1500 transmission 26000 miles 8Hp70 from 2020 Scatpack 6.4 car
Controller with harness 1000
Shifter 550
Adapters mount so on 500
Steel for frame connectors 100 dollars
And counting still think I may have saved more money than I realized doing work myself and all in.
 
I need to start thinking about a drive shaft plan. CV joint style 2020 Challenger RT style then needs a slip yoke, then will need a standard 1310 U joint on a 8 1/4 rear end. I ordered my shifter today not cheap the Challenger 8HP shifter and the knob itself 550 from Sound German Automotive. I may go to Tulsa as I'm told that Driveshaft inc does excellent work. If I get that I will have in theory all I need to complete the swap. In about tapped out on spending money I will be pissed if I hate this lol!

So far 1500 transmission 26000 miles 8Hp70 from 2020 Scatpack 6.4 car
Controller with harness 1000
Shifter 550
Adapters mount so on 500
Steel for frame connectors 100 dollars
And counting still think I may have saved more money than I realized doing work myself and all in.
Driveshaft in my A100 with a Hemi/8HP70 swap

Screenshot_20240322-124821_Gallery.jpg
 
I managed to get 99 percent done and I am ready to test drive. Before I do I need to finish up my tunnel top, small under trans brace on lower crossmember, and bolt in the interior. I also installed new drive shaft from drive shaft incorporated out of Tulsa Oklahoma. 449 dollars and some change brand new. I did have to work with Russel Drake on my RPM out we repinned in the PCS controller to speed in 2 and were working great. He did a few filters and adjusted in about 15 minutes. Goes in gear no issues and no other issues or codes. I have a switch I will throw in to flip to Sport mode off pin 3 single throw 12 volt. When switched on pin reads 12 volt and your in play mode.

IMG20240522203755.jpg


IMG20240522203740.jpg


IMG20240517081959.jpg


IMG20240508211751.jpg


IMG20240508174112.jpg


IMG20240504090422.jpg


IMG20240502163253.jpg


IMG20240521205656.jpg


IMG20240502161118.jpg


IMG20240430145828.jpg
 
Test drive today uneventful need to check fluid I cycled gears and in drive few times first then filled again. Now I need to check one last time since it had a chance to really pump the fluid some more.
 
Hopefully he adds a follow up, but here a drive report at one point.

74 Dart 360 Sport
Yea, I stumbled onto that after posting here. I like the way he did his tunnel.. Sure looks like a beach seat would be just fine. I gotta get past the shifter.. I don't want A console and don't care for the dial. I know sga had a push button unit at one time...
 
Looks like even Blueprint Engines has jumped on the 8HP bandwagon.

BluePrint LS ZF 8-Speed Engine And Transmission Packages

Considering that GM has an 8 and 10 speed auto, seems like pretty high praise for BP to cast their own bellhousing to bolt an 8HP to an LS.

That's awesome, kinda makes sense though considering the 8HP got a 10+ year jump on the GM/Ford 10-speed and is a proven design used by several makes. The GM/Ford unit is only used by them and has had issues, enough to have a few class-action lawsuits filed against them lol. Allegedly they even based the 10-speed off the ZF design but somehow made it not any better, arguably worse in some ways, go figure.

Ford–GM 10-speed automatic transmission - Wikipedia
 
That's pretty interesting. The info I've heard is that Mopar doesn't sell crate 8HP70s because ZF refused to allow it. The trans only lives because of torque management, and without a link between the ECU and TCU to support calls for reduced torque on shifts, they'll die.

The Sound German setup either talks to the Hemi ECU over CAN and works like stock, or has an output for aftermarket ECUs to ask for reduced timing. The other controllers like HTG and Turbo Lamik that replace the TCU entirely also ask for reduced power on shifts, but try to keep it alive by brute force as well, faster shifting, higher pressures, reduced number of maps, etc.

All that to say, I'm really interested in how Blue-print was able to make a deal that, seemingly, Chrysler wasn't able to make happen. They were talking about finally making them available as the Torqueflight 8, but nothing has been announced besides some of the Roadkill nights sponsored teams getting 8HPs with their Hurricrate engines.
Looks like even Blueprint Engines has jumped on the 8HP bandwagon.

BluePrint LS ZF 8-Speed Engine And Transmission Packages

Considering that GM has an 8 and 10 speed auto, seems like pretty high praise for BP to cast their own bellhousing to bolt an 8HP to an LS.
 
Hopefully he adds a follow up, but here a drive report at one point.

74 Dart 360 Sport
A follow up alright. She ran an 11.25 ET first time at strip smoking tires run lol. What else it's a noisy transmission a little bit. Shifts great and I abuse my Dart Sport every chance I can. I love the Challenger console and Charger seats with the 8 HP shifter. I mostly only use track mode, I can have Russel Drake at Sound German Automotive program the transmission as well custom tune. I plan to go that route but track mode is fine for now. I am not going to change out the 2.94 but a 3.27 rear gear might be ok but no need lol you got eight gears. Program the transmission. Don't start goofing with gears you will jack things all up this is not a 727 or 3 speed 904. Challenger runs a 3.07 if that tells you anything. I have not found a rear end yet near me in NE Oklahoma for a fair price.

I do need an Eaton True track I can smoke off my tires easily from a 40 mph rolling start. I do not have ECU torque management with my setup my understanding from Russell is he can manage how it shifts and it's all in the install. You can log the torque mapping while driving and then adjust your torque maps for gears which I probably am over due for some logging and changes. I would never ever go back to a 904/727 or a four speed. My big mutha thumper cam loves the stock 6.4 torque converter and the shift points for scat pack fit my build to a T. I set my rev limiter at 6400 RPM with Pertronix Ignitor 3 and the ZF by default shifts at 6300 so it perfect I have hit it a few times you can hear it.

Buddy has a stroked 351 Cleveland 70 Mustang punched out and stroked 393 with a 4 speed overdrive. Thunder down under heads and 550HP when ran on dino. I beat his car up everytime we launch I get him all the way down road and can pull him as well. Ran him down last time. I need brakes and other stuff car is way to fast I didn't think it would run like it does now. It's a game changer and I drive it all the time. Grocery store for wife to work often and a few all day trips for about 200 miles each and it's amazing. Try 81 mph on the highway at 2100 rpm listening to radio.

dsc03987.jpg


dsc03995.jpg


dsc04000.jpg


IMG20240628144219.jpg


IMG20240628144201.jpg
 
@4.7Light
Great report. Hope to run into you sometime around Oklahoma. I would like to use this transmission in something down the road. I'm going to check out Driveshaft Inc. in Tulsa.
 
Couple different people talking about controllers throughout this thread. Anyone look into the MaxxEcu or better yet have any first hand experience with it?
 
Couple different people talking about controllers throughout this thread. Anyone look into the MaxxEcu or better yet have any first hand experience with it?
Sound German is fairly priced works amazing and no need to crack open transmission. Comes with the harness and easy to program.
 
-
Back
Top