2006 5.7Hemi and 2013 8HP70 Install challenges and solutions

[Buckminster]

Good Morning all. I started a new forum post as I haven't seen some of the issues I'm encountering posted so I figured I'd share my experiences with you so you can hopefully learn without having to do this the hard way.

First off, there are a lot of different combinations out there, so here is the combination I'm using.
2006 5.7L Hemi. stock
2013 8HP70 transmission. stock
Holley Blackheart Engine mounts BHS566
Holley Blackheart transmission mount BHS567
Holley Transmission mount 71223029HKR
Holley cast iron manifolds BHS582

I chose this combination since it was supposed to minimize the need to modify the transmission tunnel.

I was planning on using the stock steering box, since i had it rebuilt by Steer and Gear and it is fantastic. However, it hit's the exhaust. I picked up a set of Jeep manifolds from the junkyard, since they were supposed to be the lowest profile smallest option as a backup. However both hit the manifold. I have ordered a Borgeson steering box, to try. On Holley's site, it does not mention that it will fit with the factory PS box. However in the instructions in one view it shows the factory box, then with the engine in, it does not show the PS box.

The notes are extensive about how to trim the suggested factory motor mounts, and having done that, they fit fine. The other thing that has conflicting information is the Hemi AC unit. In one spot it mentions having to clearance the K-frame. This is required. However, it does not say which units will fit. I have on the compressor I have a mount for a bolt at the back of the compressor. I had to remove that off the compressor for it to fit with the motor mount. Keep that in mind as your brand new compressor will have to be modified. I got mine out of a fully working car, so I was not as concerned since there was no warranty.

Those are my notes so far. As I uncover more, I'll post if you guys are interested. I plan on cleaning up the engine compartment once all the trial fitting is done, FYI.

 

[PLUM_72]

Nice start. I am doing a similar project. With the 8HP70 I had to remove/grind down about 7 tabs on the trans case for clearance in the tunnel. The trans vent with the Holley mounts is right behind the pinch weld in the tunnel. I cut away a couple inches of the pinch weld to run the vent line up to the engine. If I had to do it again, I would modify the vent location to the side. Someone out there makes a kit do do this. The Holley urethane trans mount is too tall in my opinion. The top of the case fit into the tunnel with the Holley mount, but was too close to the top of the tunnel in my opinion. I used a "short" trans mount from Energy Suspension that gave me a bit more clearance. The photo shows L to R the height differences - Holley, Energy Suspension Short, and the G-Force short mount

 

[Buckminster]

Nice start. I am doing a similar project. With the 8HP70 I had to removed/grind down about 7 tabs on the trans case for clearance in the tunnel. The trans vent with the Holley mounts is right behind the pinch weld in the tunnel. I cut away a couple inches of the pinch weld to run the vent line up to the engine. If I had to do it again, I would modify the vent location to the side. Someone out there makes a kit do do this. The Holley urethane trans mount is too tall in my opinion. The top of the case fit into the tunnel with the Holley mount, but was too close to the top of the tunnel in my opinion I used a "short" trans mount from Energy Suspension that gave me a bit more clearance. The photo shows L to R the height differences - Holley, Energy Suspension Short, and the G-Force short mount

View attachment 143888

View attachment 143889

Thank you for the feedback. I came to the same conclusion on the transmission mount. The last issue I have to resolve before I clean up my engine compartment is what steering to use. the Holley hits their cast exhaust manifold hard. I ordered a Borgeson steering box in hopes that it clears. If not, I'm not crazy about bucking up for an aftermarket tubular K-frame. What are you using for steering and exhaust? I should have mentioned that I removed the same lugs from the transmission to make it fit. I did see that on one of the Forum posts. Lastly, I cut the floor in the area of the vent and built a small dog house to close out the sheet metal. I recall the factory AC box being tight in this area, but we'll cross that bridge when we come to it.

 

[PLUM_72]

Nice solution for the vent. Call it an inspection hole. LOL! For a steering box, I am using the Borgeson. For the exhaust, I found the Holley/Blackheart headers (I began buying stuff several years back and was able to get a set). I did have to slightly dent the Blackheart headers to fit the Borgeson box. On the Borgeson box, I changed one of the four hex bolts around the sector shaft to a button head to give extra clearance for the headers. The Borgeson is smaller, but its smaller in many of the areas it doesnt need to be smaller. With the AC compressor, know that the later model factory AC compressors will not work as they are variable controlled. You need a pre-2014 compressor as those cycle on and off. Look at the Mopar/Direct Connection Crate Hemi AC add on kit. Download the instructions. In the instructions it gives the factory part number for the compressor. Then go to Rock Auto and buy a reman AC compressor that fits that P/N. I did follow the Holley instructions in their engine mount sheet and slightly trimmed one side of the bracket on the K-member. I dont think you need to do this for the AC compressor to fit, however, if you don't you may not get the back lower bolt out (or in) that attaches the AC compressor to the engine.

 

[Buckminster]

Nice solution for the vent. Call it an inspection hole. LOL! For a steering box, I am using the Borgeson. For the exhaust, I found the Holley/Blackheart headers (I began buying stuff several years back and was able to get a set). I did have to slightly dent the Blackheart headers to fit the Borgeson box. On the Borgeson box, I changed one of the four hex bolts around the sector shaft to a button head to give extra clearance for the headers. The Borgeson is smaller, but its smaller in many of the areas it doesnt need to be smaller. With the AC compressor, know that the later model factory AC compressors will not work as they are variable controlled. You need a pre-2014 compressor as those cycle on and off. Look at the Mopar/Direct Connection Crate Hemi AC add on kit. Download the instructions. In the instructions it gives the factory part number for the compressor. Then go to Rock Auto and buy a reman AC compressor that fits that P/N. I did follow the Holley instructions in their engine mount sheet and slightly trimmed one side of the bracket on the K-member. I dont think you need to do this for the AC compressor to fit, however, if you don't you may not get the back lower bolt out (or in) that attaches the AC compressor to the engine.

My engine was from a 2006, so I am planning on using the AC compressor that came with it. I had to saw off one of the casting lugs on the compressor, but figured that was an easy mod. It is ironic. I've been doing research for 2 years while my car was in the shop, and until I started looking into a solution for where to install the PCM and the Transmission controller, I didn't see any discussion about the variable compression AC compressor. But fortunately, the early compressor is supposed to work. I did make a small "doghouse" to go over the vent hole. The doghouse turned out well, but my welding leaves a bit to be desired. Thanks again for the info. I have the Holley Cast iron manifolds.

 

[Buckminster]

Update. I got to the point where I had all clearances fixed, had the steering box not hitting the exhaust and the engine in for what I hoped would be the last time. Then, I looked at the car from the side and noticed that the trans oil pan was very close to the ground. Once again, all the research I did said these mounts would work without trans tunnel modification. What I hadn't seen was minimal ground clearance to the pan mentioned. This is a non-starter. for any practical street driving, 3 1/2" of clearance is not going to work. so, I bit the bullet and decided to remove the trans tunnel and modify the torsion bar cross member. Exactly what I was trying to avoid.

 

[Buckminster]

The trans tunnel required quite a bit of work. The photo below represents about 50 hours worth of work. For a fabricator, probably a good afternoon, but never having done it before, I was learning as I went. In the end, I'm glad I did the update. I would not have been happy if I got the car on the road and took out the oil pan at the first bump.

 

[Buckminster]

The other issue i noted was that the engine was tilted down 6 degrees in the back, which would have been a lot for the drivetrain. now the tail-shaft is down 3 degrees. I'm optimistic that this will make for a more pleasant drive (no vibration). The last photo was taken before the sheet metal was welded into the torsion bar brace.

 

[R4Sedan]

Nice write up. Thanks for sharing.

 

[Buckminster]

Nice write up. Thanks for sharing.

I'm hoping others can benefit from my "learning" experience.

 

[Katfish]

Looks good, nice work.
My 518 hangs lower than I'd like, but that initial 3.5" clearance would have been a disaster.

 

[PLUM_72]

Interesting findings. On my 392/8HP70 swap in a Challenger, I have about 5-1/2" of clearance from the bottom of the trans pan to the ground. This is probably in the realm of where these cars were initially. There is probably more clearance here than with my old Blackjack headers from the old small block. I had no major tunnel mods, just cutting a part of the pinch weld for the trans vent I used the Holley swap engine mounts, trans mount/brackets, and Mancini Mag Mount rubber engine mounts My car runs a 215/65-15 up front and a 245/60-15 rear tire. My t-bars probably need some ride height adjustment and definitely a wheel alignment after the swap, but that will wait unit spring. My ride height adhjustment with the t-bars didn't change from my old small block, I had about 24" from the ground to the top of the fender wheel lip. My trans is tight in the tunnel, but there is a small bit of clearance all around. It is most tight around the top of the tunnel and the back portion of the trans, say the 12-o'clock position. It all fit with the Holley rubber trans mount, but I didnt have the clearance I would have liked to have. So I used the Energy Suspension short GM mount. While I dont have an official digital angle gauge, I figure I am somewhere around 2 to 3 degrees down. Need to buy a gauge for the driveshaft set-up/measurments. While the car is not road worthy yet, I don't have any concerns over the engine/trans placement at this point. I suppose if you are looking for enough clearance to put your hand in between the trans and the top of the tunnel, you should modify.

These cars are all different but I am surprised you have to modify as much as you did. Others have done this without major tunnel surgery. Look up Lukes Garage on You Tube. He has a series of videos of doing a 392/8HP70 into a 69 Charger. With the B-body there is some cutting of the t-bar cross member in the hoop area, but Holley makes a brace for this. I figured if things got too close, I could use this, but didnt need to.

There are a couple You Tube short videos from Clint Woods on the 392/8HP70 into a 74 Challenger. No major tunnel surgery there either. Just the standard cutting the tabs off the transmission.

Once mine is on the road, we will see what happens...Its been an expensive but fun project so far.