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5.7 Hemi Engine swap on 70 RR (Project)


Well-Known Member
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8:19 PM
Aug 12, 2017
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Frisco, Texas
Picked up a new project - 1970 RR, originally 383 4-speed. I've always wanted to do a conversion and found this one which was already started (many are telling me to put a 383 4-speed back in, but I've done the numbers matching project and am ready to do something new). Came with new 5.7 crate and a new 5-speed Tremec transmission. Has a Quicktime Bellhousing and I believe a Ram clutch which is hydraulically operated. Trans and motor are in car but I took trans out because I found the throw-out bearing in the parts box (someone didn't have a clue). My first problem is the "Hurst driveline conversion kit has a bunch of stuff, and I have no installation instructions. Went to Hurst website - nothing. There is a guy on U-Tube doing a mustang, but this kit is suppose to be for a 70 RR. So here I start and I'am going to need help from you experts, but please limit the clutter and opinions. I want this thread to be informative for other attempting this conversion. Thanks in advance.
Starting with a freshly painted Orange 1970 RR. Rear quarters look to be replaced and maybe front fenders. Looks to be a rust free body with trunk and floor pans in excellent condition. Hoping for a sure-grip with 355's, but haven't check it yet. Has drums all around, but suspension and rear end look to be in excellent shape - no power brake or steering. Interior is decent with deluxe panels and seat covers. Gauges are rally with tic-toc tach and 150 MPH speedo (showing around 95K miles). Has no radio but has a switch on dash for the operation of the air grabber hood (not sure how it going to work with the little hemi, but I going to make it work). The shifter is a pistol grip. Painter didn't put fender tag on car and right now it's presume missing, but I have a lead on the painter and am looking to find it. Vin number is RM23NOG188823. No build sheet on the back seat. First problem to solve is getting the installation instruction from Hurst.
Nice project and look forward to seeing more; but for the love of God, get that crap off of your fenders before you end up needing a repaint.
Nice project and look forward to seeing more; but for the love of God, get that crap off of your fenders before you end up needing a repaint.
Good Idea, and thanks for your concern. Today I was on the phone all day getting documentation. Thanks to Quicktime, Ram Clutches, Hurst Driveline Convertion and Tremec Transmissions. All were helpful. I believe I have enough information to start. A few problems - a set of ITT57HC headers came with the car. I talked with ITT and they said the header were built for the starter being on the drivers side. http://www.ttiexhaust.com/MoparClassics-Headers/57HC-134/TTi57HC.htm The bell-housing is made for the starter being on the passenger side. https://www.holley.com/products/drivetrain/bellhousings/bellhousings/parts/RM-8076 Got a set of stock manifolds and they look like they are going to work great. To bad because the ceramic/chrome headers would of looked good - I'll wait to see if the ITT folks were wrong but it doesn't look good for headers (anyone need a set?). Tomorrow I'm going to try and align the bell housing with the crankshaft, and fit the Ram hydraulic release bearing on the transmission.





I have a car 5.7 in my 70 GTX and headers will NOT work. Can't get them astound the starter, I am running the Nag1 5speed auto that came with the engine. I talked to an engineer at TTI and he told me he personally has tried to make a set and he could not make the flow right due to the bends required. I ran with the stock manifolds, they are so short I don't think any HP gain would be worth there hassle unless you are racing. I sure like the power mine makes!
I have a car 5.7 in my 70 GTX and headers will NOT work. Can't get them astound the starter, I am running the Nag1 5speed auto that came with the engine. I talked to an engineer at TTI and he told me he personally has tried to make a set and he could not make the flow right due to the bends required. I ran with the stock manifolds, they are so short I don't think any HP gain would be worth there hassle unless you are racing. I sure like the power mine makes!
Thanks Darius, your post will save some time - won't even try it.
Today we put the tranny back in. It was interesting. We check the alignment of the crankshaft and the bell housing and it was good. Also followed the instruction for the hydrophilic throw out bearing measurement and we came out with .125 or 1/8 inch which is perfect - didn't have to use any shims. One problem - we installed the bearing on the tranny and tried to install the tranny on bell housing - not going to happen - lines were in the way. We had to pull the tranny back out take the bearing off and place the bearing inside the bell housing, and as we put the tranny in place we placed the bearing on the tranny shaft from inside the bell housing. A little struggle but it happened. The instructions say to install the tranny and bell housing together. We had the bell housing bolted up already.
Have to pick up a few nuts and bolts and finish the install on the tranny, then it is on to the clutch peddle. Also need to measure the distance form the transmission tail to the differential and get the driveshaft ordered.
One note; When you have and engine, tranny, bell housing, and clutch made by different folks there is going to be problems. Just have to take you time and not get frustrated. Have to make it fun....




So I haven't work on the RR in a few days. My wife "reminded" me that there were greater priorities I must "enjoy" first. Did work on it this evening a little. I pulled the stock spring off the clutch pedal and am preparing to drill a hole on the clutch pedal 21/4" below the pivot point. Having a little trouble and am hoping I don't have to remove the pedal assembly - heard that wasn't fun. Anyway, still beating hammers and turning wrenches.


Directions I received from my new friends Hurst Drive-line Conversions;
I have a clutch. Went smoothly except for a few things. Biggest problem was drilling a hole in the clutch peddle - could get a drill to it. My neighbor let me use his little dewalt impact angle drill attachment. Couldn't get to it with that until I took the steering column out. Then this little attachment drill right through it. I attached the linkage and bled the clutch. Al working great.






Ok, now I want to get this running - starting with the starter. Went to Auto-zone and they let me borrow a few of their starters and the one that fit on my quick-link bell-housing was a late model Challenger. It installed easy enough - 3 bolts and ready for wiring. Nothing is that easy - right. I moved the steering back and forth and the drag link is hitting the starter to the point of sticking. Not sure how to fix this problem - any ideas out there? Hoping a starter from another company may work.


I’d grind a bit on the idler, just enough to clear.
Good morning. Can you give any info on the M/S mount and seal? I need that for my install. Beautiful car. Hope my car comes out half that nice. Clint.
Yes, try to work on it a little every day - but it's slow - seems like everything I have to do is custom. This is not a project for a beginner. I've been working on the fuel system. This car was stored for a long time and the fuel tank was full of vinegar - the worst I've ever seen ( enough to make you barf). I replaced the tank and fuel lines. Also installed a Mercedes external fuel pump - I just couldn't bring myself to put an electric motor inside a gas tank. This Mercedes pump is a bar 5 (meaning it produces 72.5 pounds of pressure). The engine rails need 58 so I also installed a fuel pressure regulator. It came out nice, but took some time.


Fuel completed. I got ahead of myself because a friend of mind was going back to 500 wheels, so I bought his Cragars. I love the look and always wanted a set.


As you can see I also had my hood painted, and am in the process of adjusting.
Right now I'm working on my driveshaft. Ordering one tomorrow from Strange Engineering and was doing the required measurements this evening.


489 rear end - suppose to be the strongest 8 3/4.

What else - I just keep ordering parts and installing them as they come. Inter fenders, new bumpers and lights, rewiring everything. I'm trying to get to the point where I can start it - that will excite me to move forward. To answer your question - there's lots of progress. I just been to lazy to post it - will try to do better.
Forgot to mention the V code Super Bee I'm working on also. Needs some TLC but it's starting to come along. Had the carbs rebuilt and now it's running strong. Harold Demes rebuilt them and I didn't even have to adjust them after putting them on. He is a master carb builder. His contact is 6306057218 if someone needs a 6pack rebuilt.

Still working on the RR. Thought is was necessary to install power steering (since I had a power steering pump on the motor). I had a power steering pump off a 70 Super Bee and tried to put it on but it hit the manifold. I took some metal off the the pump by grinding and little and no go. I ended up buying a new pump that was smaller and had a tighter ratio. To get this one in there I had to cut the heat shield a little but it's in there. Of course had to rebuild the front end - bushing, ball joints, tie rod ends, and while I was at it might as well add some front disk brakes and put a power booster so I can have power everything. The conversion kit was of great quality but the directions sucked - had to figured it out, but it's on and working I guess. I have a few thing to finish 1. the steering column needs to be cut and fitted with an adapter to work with the new pump and 2. because the pump is close to the manifold I want to run the low pressure side through the radiator (because it's a 5 speed I don't need the trans cooler) to cool off the pump fluid. Without a cooler the fluid can exceed over 230 - the trans cooler should kept it around 160. My wife wants to buy me a vintage air system for this car for Christmas and I do live in Texas, but I getting worn out. Have so much still to do. Will update again soon.

I moved the clutch fluid res. behind the booster - thought it came out great...
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I am considering this exact swap for my '70 RR. Currently running an Edelbrock/rail injected 440/Hurst driveline conversion TKO 600 setup (LOVE THE 5 SPEED!).... I think the $ to HP is about equal until you factor in the cost of retrofitting modern accessories, fuel mileage, and EFI conversion cost.... then this swap makes sense... hanging on your every post!
Awesome build. I too have a 70 RR that I am going to build. I have a 66 426 for it but had considered going 5.7 at one point just for the reliability. Current plan is to stick to the 426. Was an AT car but will be converting it to a 4 spd and of course will be running a air grabber hood.
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