5.9 Magnum driveline swap into 71 Fury

[justthatguy]

Hey everyone,

So I've given it a bit of thought about what to do with my Fury-sans engine, originally considering a big block, then an LA 360 (which is what it had) but I think since I'll mostly be cruising with it, I'm going to do a 5.9 with a 46rh. Now, full disclosure, I've never done this before, so I'm creating this thread to mostly ask for help if I need it.

I will be switching to carb and an older style ignition(I may even use the stock one with the car, it looks recently replaced). I do intend to use the PATC kit for the automatic operation of the 46rh. I will be keeping the serpentine drive for the accessories, and might go to an electric fan, but I'll see if I can't get the old style fan to work. I'm keeping the compressor, because I might can junkyard an AC system for this thing later on.

It's a HD drum car(which I'll unfortunately have to use for a while, can't afford to do it all at once) and it has an 8 1/4, which I don't plan to replace. I really doubt a 5.9 with a cam is going to pose it much of a threat. I'll also be using the stock lockup torque converter too, since it's probably once again not a bad selection for a warm 360. It'll have around probably .500 of lift, and probably off the shelf, but I don't know just yet since my main focus is 400 ft lbs of torque with an air gap and 600 to 650 sized carb. Suggestions welcome. I'm not replacing the heads until I can afford engine quests, it's not worth it to me to slap Chinese heads on it to take em right back off in 2500 miles.

I'm probably going to replace the gears in it with 4.10s, with limited slip if I can get it, I'd imagine a junkyard Jeep is my option here. I know the liberty came with the 8 1/4 and some Dakotas did too, so we'll see if I can use those. I'll have to find an older carrier because of the older spline count but I doubt this to be an issue. Lots of A body guys around here.

I'll probably have to shorten the driveshaft 3.5 inches from what I've read, and have to get a 46rh yoke, but that shouldn't be a problem either. Junkyard to the rescue.

If it's not apparent yet, the goal here is cheap. The car will be incrementally upgraded until I'm happy with it, how fast is determined on how my jobs look in a few years, but the focus right now is to get it driving. Then I can worry about the other stuff. It'll eventually get new suspension, springs, t bars, and front discs, and finally a respray with it's original B2, but that's a ways off yet.

I'll be posting my snail's pace progress here as I get stuff done. I'll be picking up a 360 tomorrow and a 46rh Wednesday but with the hellacious southern winter they're predicting I don't imagine much progress to be made until spring. That said, anyone have concerns or advice so far?

 

[cantflip]

Hey everyone,

So I've given it a bit of thought about what to do with my Fury-sans engine, originally considering a big block, then an LA 360 (which is what it had) but I think since I'll mostly be cruising with it, I'm going to do a 5.9 with a 46rh. Now, full disclosure, I've never done this before, so I'm creating this thread to mostly ask for help if I need it.

That said, anyone have concerns or advice so far?

Sure... but you may not like it...

IMO it's clear that you are emulating a magazine type build vs swap experience... stop and think this through for just a moment prior to spending money...

Buy a complete running P/U with the drive line you want. Clean it up, Gunk and a garden hose will do... pressure washer not a worthy investment, but if you have one... paint it a correct color to blend into the new environment... the paint will save you lots of rusty fasteners later, but needn't be a show quality job.

Swap the drive line complete, as is, and get the appropriate FSM for the year donor truck you used, as well as the appropriate FSM for your Fury. Use the wiring harnesses and computers from the donor, and don't toss anything electronic... you may need it later. Shortening the truck driveshaft or just building you a custom new driveshaft should be cheap ($100-200, but it has been a while), I'd recommend towing it to the drive line shop, after it's running, so they can measure and install it for you.

You will find countless little PITA things you have to work out to make this swap function correctly, but with a full donor that runs prior to the swap, you will have your best chances for making this work. If you continue with the magazine build, you will invest many times the money and have a far less chance of a driveable outcome.

The part of this idea I like, is you will continue to have the benefits of the donor vehicle (port fuel injection, proper transmission operation, the donor's self diagnostic abilities...) and the style of the Fury. BTW, just fix the brakes... you can jump of that cliff much later if you insist... drums are probably going to work fine for cruising, so long as they are working properly.

A custom fuel tank should be the biggest hurdle... consider having it made in stainless... $$ up front, but with a drain plug, it should save you grief once finished.

 

[commando1]

IMO it's clear that you are emulating a magazine type build vs swap experience... stop and think this through for just a moment prior to spending money...

 

[jct]

If i would be doing something like this, i'd leave the ign and FI on it for dependability, but that's just me...

 

[azblackhemi]

This has a 5.9 Magnum driveline in it. In this case the body was dropped on the whole chassis.

 

[360Magnum]

If u wanna go cheap and have plenty of power do this. Pick up a 5.9 Mag motor. Try a junk yard, craigslist etc... Alot of times u can hear them run etc... Convert it over to carb and install a 360 la car-center sump oil pan and oil tube and pick up. 318 la will not work and a magnum oil pan will not fit in the car.

Install a la distributor your choice on that the magnum distributor will not work running a carb. Then use a la style timing chain cover, water pump etc... and you will need your brackets etc.. You can buy these parts used or new or even pick up a donor la motor for the parts. U can pick up complete la motors usually 318's for $100. Just remember you need a 360 la car-center sump oil pan.

Stock motor mounts on your car will work on a 5.9 mag as your was a 360 car. Magnums have provisions for the older style mounts. Then you can decide what kind of fuel pump to run. You can run a electric fuel pump in line with a regulator or just get a cam extension from Hughes and run a mechanical fuel pump.

Right here with this swap you basically have Horsepower: 300 and Torque: 375 same as the old Mopar Performance crate motor specs. Cause all they were was the same 5.9 motors in the trucks etc.. except running carb. Same cam etc...

Yes the stock magnum heads are prone to cracking between the intake and exhaust valves you can still use them there are plenty of stock magnum motors out there with these cracks and there still going. If you think it may be a issue take them to machine shop and have them leak and pressure tested to make coolant wont leak into the chamber and compression wont leak into the ports. But I would just run them. Stock magnum heads will support 400 hp at the crank. If you wanna do a cam change you will have to upgrade the stock springs and retainers on the heads. With a cam change its very easy to get 380-400 hp out of one of these.

As far as the tranny I would run a 727 or 904 you will also need a stock 5.9 flexplate. One hole will need to be opened up about 1/8 or so, not much. Use a neutral balance converter . With the 46RH you will have to modify the cross member and I believe the tunnel also. On the rear if you wanted to change gears in the 8.25 rear you need stuff from a rear with 27 spine axles. These motors have a very low wear amount than V8's used to have. When budget allows get better heads port them bigger cam etc........ May want to throw a new timing chain on it maybe even new bearings if you like. But look for a clean 5.9 mag and just convert it over to carb and enjoy it as is. Easy swap and can be cheaply done. May have forgotten something but there is plenty of info out there on this basic swap. Im building a 5.9 mag for my 72 Polara. Im going a little different route but for the $ these can not be beat. Just my opinion

 

[360Magnum]

Also use the magnum starter also. Just with this basic swap you will have a nice riding Fury, plenty of power, vaccum etc.. And best of all it will be cheap.

 

[Polaraco]

I did this years ago already. 72 Polara AKA Polaraco. Featured twice in Mopar action. It included the factory computer, EFI and the 518 trans. Darn car got 26 on the highway. Piece of cake

 

[CBODY67]

Regarding "magazine builds", when I finally got the guts to do an intake manifold swap on my '67 Newport 383, I pretty much knew what needed to be done. But after it was all done, I came to realize that what the magazines usually put in the article is usually ONLY THE HIGH SPOTS of the operation. Which does NOT usually cover the little bits you have to chase and/or find.

The donor vehicle orientation being used is an excellent idea. Years ago, a friend was building a '67 Camaro SS/RS, back well before many of the factory-style wiring bits were readily available. He bought a '75 Impala from a salvage yard. It had all of the little things he needed, which made for a much better Camaro build. He told the salvage yard guy what he was planning on doing So when he got done, he gave it back to the salvage yard and all was better. The fact he was in a mini-storage building, he had a place to park the Impala close by.

I know that almost every OEM cam these days has over .500" lift, BUT in the earlier motors, that a bit more than just "warm", that much lift also means more duration, which makes it more "radical" than just "warmed-up", to me.

As a possible alternative to the 518 (and related floorpan tunnel massagings), you might consider a '80-era 904 family trans (998 or 999) in a non-lockup variation. When the front pump and converter are changed to remove the lock-up set-up, you can also insert the 2.75 low gear planetary. It's a 4-pinion planetary, rather than the normal 3-pinion version. The 904 family will take less power to run than a 727 family trans will. This will also mean you can delay the rear axle ratio change for much later!

The reason for the non-lockup conversion has to do with the quality of the heat treat on the converter splines (or is it the input shaft splines?). On my '80 Newport, when it was still under 100k miles, the splines wore enough that the car stopped "pulling" while going home for lunch one day. Luckily a few blocks from home. From the sound of the trans shop owner, this was somewhat common. I opted to go back with lock-up parts. Then a few years later, it happened again. We did the 2.75 low gear set at that time, but kept the lock-up one more time. With the 2.41 rear axle ratio, it pretty much put things back to the 2.45x2.76 low gear orientation.

Even from as far back as a 1968 article on beefing-up the 318 904 trans, it mentioned that it consumed less horsepower than a 727 did, which meant more power to the ground and quicker ETs.

Just some thoughts,
CBODY67

 

[justthatguy]

Well, actually, I wasn't going for a magazine build. I want to build the car to drive it. I don't want a screaming race motor. The idea came to me as I was thinking about putting a 700r4 on a big block and I thought that it'd be cool to do a magnum in it since a 360 is what it had originally, but I was pretty sure too that someone else decades ago figured that out so I've done some reading and hopefully selected my parts carefully.

I want the 518 so I can run 4.10s and still have a reasonable cruising rpm with lockup for efficiency. I'm aware this involves modifying the trans tunnel and crossmember, nothing I can't do or haven't done before.


I bought a 360 magnum today with 105k on the clock and got EVERYTHING with it, he didn't even cut the harness. It's a shame it's a PITA to run the FI with anything else than stock, fuel injection would be neat. The eventual goal is a 408, and at the very least a new set of EQ heads soon, so I don't think it'll do what I want it to, even if the opportunity is there. I wonder if I could eventually megasquirt it and have it run the injection and spark. That'd be something, but I digress.

I appreciate the advice, cantflip, but I should clarify I'm not running EFI on it. I'm using an air gap and a carb. I'm not using hardly any of the truck parts, aside from the serpentine and the alternator/ps pump. I'll have to read into what basic sensors will work with the electronics in the car and which I'll have to change over to the old style stuff for the gauges and I figure on mechanical backups anyway.

I've got an electronic distributor(from a '72 duster) and all the ignition stuff was never removed from the car so I more or less anticipate few hang ups, though I know there will be some.

I am pretty sure that I have the correct carrier for the gear swap, be it open, but if I don't I'm not worried, though it's aggravating that the 29 spline posi carriers are like $50 cheaper on average than the 27 spline. I'm okay with a one tire fire right now, I'll deal with that after the brakes. I plan on keeping the drums right now since I won't be corner carving in a land yacht, they should be fine. I will go to disc because I would like to make it safe enough for extended road trips and there's less to go wrong on a brand new set of discs than 50 year old drums.

The AC is not even a consideration in the install, but I have a 134 compressor now and I could potentially do it, if difficult, in the future.

 

[justthatguy]

One of the reasons for a magnum versus a la is that they are usually in MUCH better shape and sometimes cheaper too. As far as the driveshaft, I will have a master mechanic and drag racer of wild weird cars helping me on the install, and he'll be greatly helpful with the fabricating aspect since my welds looks like someone did it with their foot.

I also doubt I'll need a custom fuel tank with a low pressure pump and a 600 cfm carb. That's about what was on it in the first place. If I was using the FI, maybe something designed to work with high pressures, like an LX or LH mopar. Not that I would, but speculation.

This is basically a reinstall of the original drivetrain, just with extra goodies.

 

[justthatguy]

I will get the driveshaft professionally done, I'm just figuring on roughly 3.5" since I know that's a number I keep hearing when people do these swaps.

 

[justthatguy]

If u wanna go cheap and have plenty of power do this. Pick up a 5.9 Mag motor. Try a junk yard, craigslist etc... Alot of times u can hear them run etc... Convert it over to carb and install a 360 la car-center sump oil pan and oil tube and pick up. 318 la will not work and a magnum oil pan will not fit in the car.

Install a la distributor your choice on that the magnum distributor will not work running a carb. Then use a la style timing chain cover, water pump etc... and you will need your brackets etc.. You can buy these parts used or new or even pick up a donor la motor for the parts. U can pick up complete la motors usually 318's for $100. Just remember you need a 360 la car-center sump oil pan.

Stock motor mounts on your car will work on a 5.9 mag as your was a 360 car. Magnums have provisions for the older style mounts. Then you can decide what kind of fuel pump to run. You can run a electric fuel pump in line with a regulator or just get a cam extension from Hughes and run a mechanical fuel pump.

Right here with this swap you basically have Horsepower: 300 and Torque: 375 same as the old Mopar Performance crate motor specs. Cause all they were was the same 5.9 motors in the trucks etc.. except running carb. Same cam etc...

Yes the stock magnum heads are prone to cracking between the intake and exhaust valves you can still use them there are plenty of stock magnum motors out there with these cracks and there still going. If you think it may be a issue take them to machine shop and have them leak and pressure tested to make coolant wont leak into the chamber and compression wont leak into the ports. But I would just run them. Stock magnum heads will support 400 hp at the crank. If you wanna do a cam change you will have to upgrade the stock springs and retainers on the heads. With a cam change its very easy to get 380-400 hp out of one of these.

As far as the tranny I would run a 727 or 904 you will also need a stock 5.9 flexplate. One hole will need to be opened up about 1/8 or so, not much. Use a neutral balance converter . With the 46RH you will have to modify the cross member and I believe the tunnel also. On the rear if you wanted to change gears in the 8.25 rear you need stuff from a rear with 27 spine axles. These motors have a very low wear amount than V8's used to have. When budget allows get better heads port them bigger cam etc........ May want to throw a new timing chain on it maybe even new bearings if you like. But look for a clean 5.9 mag and just convert it over to carb and enjoy it as is. Easy swap and can be cheaply done. May have forgotten something but there is plenty of info out there on this basic swap. Im building a 5.9 mag for my 72 Polara. Im going a little different route but for the $ these can not be beat. Just my opinion

This is basically EXACTLY what I'm doing, just a different trans.

 

[cantflip]

Well, actually, I wasn't going for a magazine build. I want to build the car to drive it. I don't want a screaming race motor. The idea came to me as I was thinking about putting a 700r4 on a big block and I thought that it'd be cool to do a magnum in it since a 360 is what it had originally, but I was pretty sure too that someone else decades ago figured that out so I've done some reading and hopefully selected my parts carefully.

I want the 518 so I can run 4.10s and still have a reasonable cruising rpm with lockup for efficiency. I'm aware this involves modifying the trans tunnel and crossmember, nothing I can't do or haven't done before.


I bought a 360 magnum today with 105k on the clock and got EVERYTHING with it, he didn't even cut the harness. It's a shame it's a PITA to run the FI with anything else than stock, fuel injection would be neat. The eventual goal is a 408, and at the very least a new set of EQ heads soon, so I don't think it'll do what I want it to, even if the opportunity is there. I wonder if I could eventually megasquirt it and have it run the injection and spark. That'd be something, but I digress.

I appreciate the advice, cantflip, but I should clarify I'm not running EFI on it. I'm using an air gap and a carb. I'm not using hardly any of the truck parts, aside from the serpentine and the alternator/ps pump. I'll have to read into what basic sensors will work with the electronics in the car and which I'll have to change over to the old style stuff for the gauges and I figure on mechanical backups anyway.

I've got an electronic distributor(from a '72 duster) and all the ignition stuff was never removed from the car so I more or less anticipate few hang ups, though I know there will be some.

I am pretty sure that I have the correct carrier for the gear swap, be it open, but if I don't I'm not worried, though it's aggravating that the 29 spline posi carriers are like $50 cheaper on average than the 27 spline. I'm okay with a one tire fire right now, I'll deal with that after the brakes. I plan on keeping the drums right now since I won't be corner carving in a land yacht, they should be fine. I will go to disc because I would like to make it safe enough for extended road trips and there's less to go wrong on a brand new set of discs than 50 year old drums.

The AC is not even a consideration in the install, but I have a 134 compressor now and I could potentially do it, if difficult, in the future.

Good luck, document the build here... low points too... if nothing else, it will serve as a reference for those who choose to emulate the build.

Since you are going with a carburetor, the stock tank will do, just make sure it's clean.

 

[justthatguy]

Picked up this 5.9 Monday. 105k on the clock, I have a distributor off a 318 already and I think I have a Carter avs too. I might have a thermoquad but I don't think I'd use that. I picked up a 46rh Wednesday, but I haven't gotten a chance to mess with that yet. Next up is the oil pan and pickup, and then the intake. Looking at the setup, I need a kickdown rod off a 360 which i also believe I have so that leaves the cam, timing set, patc kit, and gasket set, and she'll be ready to roll.

 

[65sporty]

The 46RH uses a cable for it's TV linkage, check out Lokar for a kit as the stock one wont work with your carb.

 

[justthatguy]

The 46RH uses a cable for it's TV linkage, check out Lokar for a kit as the stock one wont work with your carb.

Any particular length or is it a generic kit?

 

[65sporty]

Any particular length or is it a generic kit?

Lokar has kits for Mopar applications.
Summit has them
Lokar Automatic Transmission Kickdown Cables - Mopar Transmission Make - A-518 Transmission Type