392 Restomod

[mzacc]

Hello - Working on a 1970 Barracuda conv Restomod project. 392 crate but I do not believe the original 904 tranny is a good idea. I'd like to keep it Automatic with overdrive and do not want to modify the transmission tunnel. Should I install a 518? Will that fit on the existing tranny mount? I was told a 727 would require a mechanical overdrive switch of some sort. Thanks.

 

[scar426]

Hello - Working on a 1970 Barracuda conv Restomod project. 392 crate but I do not believe the original 904 tranny is a good idea. I'd like to keep it Automatic with overdrive and do not want to modify the transmission tunnel. Should I install a 518? Will that fit on the existing tranny mount? I was told a 727 would require a mechanical overdrive switch of some sort. Thanks.

Not certain, but I would look into using a 545RFE transmission, It's a bit larger than a 727/904 in the tail housing area, but i think with the right motor mounts and tranny mount you can get it to fit without cutting the trans tunnel (may need some BFH persuasion in a few spots, lol) also check with Hotwireauto.com and Chris, he has all the Harness/CPU bits you'll need.

 

[mzacc]

Not certain, but I would look into using a 545RFE transmission, It's a bit larger than a 727/904 in the tail housing area, but i think with the right motor mounts and tranny mount you can get it to fit without cutting the trans tunnel (may need some BFH persuasion in a few spots, lol) also check with Hotwireauto.com and Chris, he has all the Harness/CPU bits you'll need.

Thank you! I'll look into it.

 

[Katfish]

I have a 518 behind my 5.7 and love it.
Not a difficult install.

Good info in this thread:

Opinions Wanted: Overdrive Transmission Swap Options in Engine, Transmission & Rear End

https://postimg.cc/XXfZdQm2][/url]

 

[mzacc]

518 tranny - OK thank you!

 

[mzacc]

I'm sure you had to shorten the driveshaft, Did you have to modify your trans mount? Did it link to your console without incident? Thx

 

[Katfish]

Good info here:

518 is longer than 727, so DS needs to be shortened.
You can mod your trans mount, several places offer new that work.
I bought my mount from the source in link below.

727 to A518 swap a novice guide by 360FISH | plymouth | diys | DIY

 

[mzacc]

Awesome - Thanks. I saw a bunch of Gen3 mods from Holley. I'll keep looking for the best set-up. MZ.

 

[scar426]

Awesome - Thanks. I saw a bunch of Gen3 mods from Holley. I'll keep looking for the best set-up. MZ.

Alot of the Holley products for the Cuda swaps have been discontinued, FYI. I am using some of their products on my 392/8 spd swap and while a decent fit, I did need to make a relief cut in my tunnel and then make a cover for the 8 spd to fit. Thier engine mounts put the vent tube for the trans right on the firewall/tunnel seam and I could not "beat" it in enough. No biggie and minimal cutting of the tunnel. I believe the US Cartool mounts will allow you to move the motor fwd a bit more and not have that issue.

Side note, I know Katfish said he used a 518 with good success, but the cpu from an 05-09 (i believe) will run the 545rfe transmission, with no additional parts or controllers or the need for a modern factory shifter. Used that setup twice on 2 different builds and works great. Again, check with Chris at HOTWIREAUTO.COM for info. It really is too easy and is imo the best way to go and get a more modern transmission as well that mates to the 392 no problem. I used Lokar shifters for the transmission (trans mount on one and surface mount in cab on the other). There are different configurations to mount the shifter to your needs. CAVEAT!! neither of these was in a Cuda but am currently doing a 392/ 8 spd in my cuda. (8spd is a bit of a different animal, but not too different)

 

[PLUM_72]

A 392 with an 8HP70 auto trans (basically out of a 2020 Challenger) will slide into an ebody without modifications done to the tunnel and using the stock K-member. You will need to use the Holley engine/trans mounts which move the engine forward 1-inch. This gives the transmission some room. You will also need to trim some of the tabs/protrusions off the trans case. There are alot of photos in the forums on trimming tabs off the 8HP70.

Search YouTube for Luke's Garage. He does a 392 with 8HP70 into a 69 charger. Lots of good info! The B-body has a step where you need to modify the torsion bar cross member that is not required on an ebody. Then there is a guy Clint Woods that has a couple YouTube short videos on his You Tube page putting a 392/8HP70 into a 74 Challenger. It all fits!