8HP70 transmission in 1971 Dodge Challenger

[challboy728]

I am swapping a 5.7 Gen III hemi with 8HP70 trans into my 1971 Dodge Challenger R/T using the Holley swap kits. I am at the point where I am ready to put the K-member with motor/trans up under the car.
Does anyone have any info on the transmission / transmission tunnel modifications required. I would appreciate any information before I attempt the fit-up.
Thanks in advance!!

 

[moparleo]

Here is what you need.

USCT1M1801-70 to 74 E-Body Transmission Tunnel Perimeter Fra

store.uscartool.com

 

[challboy728]

Here is what you need.

USCT1M1801-70 to 74 E-Body Transmission Tunnel Perimeter Fra

store.uscartool.com

Thank you for your response, Moparleo. I think the Holley swap kit moves the engine and transmission further forward so cutting out the tunnel is not necessary. I am also trying to do the swap without breaking the bank!

 

[SFEbody]

I have the 8HP70 going in my 70 Barracuda, I did have to cut the torsion bar rail to fit the trans. I used the US Cartool Trans mount and b-body reinforcement.

 

[terrywalker]

This is very interesting. With the new b-body reinforcement tunnel, how will the carpet fit? I've thought about doing this to a 74 Charger i have.
Terry W.

 

[SFEbody]

Not close enough to carpet yet Terry, but soon and I will post pictures in about a month to let you know

 

[ItsJustMe]

All you gotta do is get the Holley trans mounts and slightly bend back one small area on the floorpan/ firewall pinch weld in a very small area for the transmission breather as far as body mods.

Grind off the following castings circled in red on the trans case and it’ll slide right in.

If you would rather get the U.S. car and tool trans tunnel, I’ll sell you one cheap because I bought it not knowing it would fit without it.

 

[Kris376]

All you gotta do is get the Holley trans mounts and slightly bend back one small area on the floorpan/ firewall pinch weld in a very small area for the transmission breather as far as body mods.

Grind off the following castings circled in red on the trans case and it’ll slide right in.

If you would rather get the U.S. car and tool trans tunnel, I’ll sell you one cheap because I bought it not knowing it would fit without it.

Thanks for that info! I'm going to be running an RMS K member in my Challenger for my hellcat swap but the K member is bare with no mounts (it was a big block K member, I cut the mounts off and ordered gen 3 mounts from RMS to weld on). Sounds like there is a chance if I weld the mounts on forward of the original mounting location that the trans may clear the tunnel then. Now it's just a question of whether or not the oil pan/headers clear everything when I move it forward.

What yoke is that BTW on the trans?

Also, how is accessory clearance to the radiator with the holley swap, having the engine mounted forward like that?

 

[ItsJustMe]

Thanks for that info! I'm going to be running an RMS K member in my Challenger for my hellcat swap but the K member is bare with no mounts (it was a big block K member, I cut the mounts off and ordered gen 3 mounts from RMS to weld on). Sounds like there is a chance if I weld the mounts on forward of the original mounting location that the trans may clear the tunnel then. Now it's just a question of whether or not the oil pan/headers clear everything when I move it forward.

What yoke is that BTW on the trans?

Also, how is accessory clearance to the radiator with the holley swap, having the engine mounted forward like that?

Not sure why I missed that you replied to me. You only have to move the motor mounts one inch forward. You will have plenty of room. I have the RMS with it moved 1 inch forward when they made it. Give them a call and they will give you the mounting location to weld. Tell them what you are doing and they will walk you through it. They are very helpful.

What oil pan are you using? It shouldn’t be an issue. I had to use an oil filter relocation kit because the Mopar 45 degree one won’t fit with RMS. Also TTI headers are the way to go Holley headers won’t fit. (Everything I said wont fit is for sale, ha)

 

[challboy728]

Not sure why I missed that you replied to me. You only have to move the motor mounts one inch forward. You will have plenty of room. I have the RMS with it moved 1 inch forward when they made it. Give them a call and they will give you the mounting location to weld. Tell them what you are doing and they will walk you through it. They are very helpful.

What oil pan are you using? It shouldn’t be an issue. I had to use an oil filter relocation kit because the Mopar 45 degree one won’t fit with RMS. Also TTI headers are the way to go Holley headers won’t fit. (Everything I said wont fit is for sale, ha)

Just caught up on my post. I was planning on purchasing the Holley Blackheart headers for my swap. Is the reason they won't fit because of the RMS? I am using the stock k-frame with the Holley motor mounts - the 45 degree oil filter adapter works with this setup.

 

[SFEbody]

I vaguely remember the 45 degree adapter with the filter on hit my K-frame, I had to go with the remote relocation until I decided to change to the QA1 K-frame. But, for your case, it could fit. I hope so.

 

[junkyard]

What TCU are you guys using with this transmission?