I was on Speedway's site earlier today and they sell engine turned sheets of metal in various sizes, you cut to fit. Might be an option there.

So just a little update on that 318 I had a lead on,
It is a Magnum 5.2. it is still in a Dodge Ramcharger that last lived as a snow plow. The Ramcharger was purchased as a parts truck, mostly for the interior pieces. The story was, it was running but quit one day. The codes said it was a bad sensor, but installing a new sensor did not make the truck run, but it does turn over with a good battery. The instrument cluster is gone, so I have no idea how many miles are on it. They found a different truck, and sold this one for parts. The current owner is into the Gen 3 Hemi, so he has no interest in the 5.2, and didn't waste any time trying to get it to run. If I want it, its mine for free, and I can take as much stuff connected to it as I want. I'm off seeking more info on what will interchange and what won't.

Well, you convinced me to go with the 5.2, and I got lucky to find a complete low miles runner for $600. If you get that 5.2 for free that leaves lots of budget to tune it into exactly the engine you want.

So, lots of evaluating going on here right now.
That motor is in fact a Magnum 5.2 and its free to me. That is the good news.

Now the bad news. I really want to keep the 5 speed manual trans that is on the current 3.9. Everything I've read says the 3.9 manual trans stuff bolts onto the 5.2 Magnum and would work except the motor won't run. The ignition uses pick up points located on the flywheel. A 3.9 has 9 pickup points (what I have been told ) but the 5.2 flywheel has 4 pickup points. The timing will be fired differently between the V6 and the V8 because of the pickup points. The 3.9 stuff will work on the 5.2 IF I use a different ignition. One option I have not looked into is to see if I could find a different way to pick up the timing signal, like maybe through an old lean burn locked distributor.

Not a big deal, right? Simply buy a 5.2 flywheel, new ones are even available! Except there are two versions of a 5.2 flywheel, a 92 and 93 or a 94 to 02. I don't know what year the motor actually is, but there is another slight problem. The 5.2 only has an 11" clutch (14.5" outside diameter flywheel). The 3.9 only has a 10.5" clutch (13.5 outside diameter flywheel). I suspect the 14.5" flywheel is not going to fit in a bell intended to use a 13.5" flywheel. The 3.9 bell is the only bell that matches this transmission. Are we having fun yet?

So, lets look into the ignition options so maybe we can just bolt the 3.9 stuff onto the 5.2 for however long it lasts (I have two of these same 3.9 transmissions here). There are lots of electronic ignition systems available for the 5.2. Unfortunately, most of the current after market ignition systems don't "talk" to the Chrysler fuel injection systems. I also want to keep the fuel injection.

The next option I looked into was scrapping the Chrysler EFI and going with an aftermarket fuel injection like Holly system or one of the others, but most of them are throttle body injection and use an intake manifold with a Holly carb bolt pattern. The 5.2 has the keg intake with port injection, and any SB intake around here is the old spread bore that would need modification to work on the Magnum motor and an adapter to use the Holley based throttle body. I am also unclear as to if those aftermarket systems still use the Chrysler ignition pick up off the flywheel, which wouldn't help me any way. I'm really having fun now.....

I suppose the next logical step would be to do a compression test on the 5.2 and be sure its worthy of all this effort. The reality is, this car will probably not see another 30,000 miles put on it. A new motor is not necessary, just need a good reliable used motor that is good for another 40,000 miles. I don't think the current 3.9 has that in it without a rebuild.

The Holly programmable efi system has an option for the ignition, an intake with port injection for the Magnum motor, the throttle body, wiring and sensors in a kit form for somewhere around $1600-1800. It still doesn't tell you if it uses the ignition pickup off the flywheel or not. I need someone with one of these systems to chime in here.

In addition to that price, I would need to add what ever it takes to bring the 5.2 up to snuff, tires, wheels, seats, and what ever else I may need to do with the car. The aftermarket EFI was not on the radar with this project and almost doubles the planned budget.

Another thought that is crossing my mind is the old lean burn locked (no vacuum or mechanical advance) distributors. They had the 8 point pickups in the spinning shaft the used a magnetic impulse to instruct the brain box to fire the coil. I ASSume the flywheel pick uses a similar technology, is that a direction I may be able to get the timing to function? Someone way smarter then me can probably help here as well?

If you can get the magnum and the computer and wiring for free get it.

As for fitting to the 5 spud, I'd keep looking for a smaller flywheel. Clutch itself isn't an issue.

Come to think of it, the newer 11 inch Clutch is probably really a 10.95 which should have the same bolt pattern as the 10.5. The true 11 inch did need a different flywheel. NEED TO FIND DETAILS, not just go by nominal information. I don't think the true 11 was around after the 70's.

This may just be a bolt together deal. Do they list different tooth counts for the starter ring?

Alternatively, does the 5 spud bell have dual starter bolt patterns and support pockets?

The biggest issue is, there is only one flywheel size for the V8 magnum (2 different flywheels, one for the 5.2 and one for the 5.9) but both are the same outside diameter at 14.5" The flywheel for the 3.9 only comes in one diameter, and the outside measurement for it is 13.5" The tooth count on both are the same, 143 teeth. If it was just the clutch, I'd buy a new one, but that 1" larger outside diameter isn't going to work with the bell I have.
According to everything I have read over the last two days (and that was a lot of reading) tells me the transmission I have only bolts to this bell. I have a GV2500 trans and it is the "light duty early transmission". The next step up was the AX15, which is a trans & bell combo, but also requires a flywheel with a 13.5" outside diameter. Everything with a 5.2 or a 5.9 has the larger flywheel, and a larger bell, and the full size trucks got the GV3500 trans with a matching bell, or the 4500 trans with its matching bell. During the mid 1990s, manual transmissions were hard to come by the V8 trucks got the larger diameter flywheel and the V8 got the smaller flywheel (until 97 or so, then the V6 also got the bigger flywheel, but it also got a different bell and transmission, and each manual transmission version had its own bell. There was no interchangeability except the trans and bell combo, is what I'm reading.

Both 3.9 bells I have is transmission specific, only one bolt pattern. one bell & trans was in a 90 Dakota with a 3.9, and the other was in a 91 Dakota 3.9. I haven't measured, but I don't believe that 1" larger diameter flywheel is going to even fit inside this bell, let alone have space for a starter. i replaced the clutch in this bell a little over a year ago. Its a pretty compact arrangement. everything involved with the clutch/trans is ID ed by the motor size until you get late into the 90s.

Edit: I can buy new smaller flywheels, but they are for the V6. The problem is, the ignition timing is ran off the "cam sensor" at the back of the motor, at the top of the bell. That sensor picks up the timing spots off the flywheel through a hole in the top of the bell. The V6 has 9 timing spots, but the V8s have 4 timing spots. The ignition timing won't even be close. If I could figure out a different way to notify the computer of the timing, I would just use the bell, flywheel, and trans I already have. i thought just buying a new flywheel would get the job done until I discovered the differences in the diameter. I will have to dig out my other 3.9 flywheel and have a better look at it.

They say if there is a will, there is a way. I have the will.

My 2001 Dakota has the NV3500 5spd manual behind the 4.7V8. But Dodge also put that NV3500 behind the 5.2 Magnum in the 1994 to 2004 Ram 1500. Not sure the bell housing is the same though for the 4.7 to the 5.2 Magnum. When I use my Dakota and the donor chassis under my 56 pickup build I will not be using the NV3500, I have a 8HP-70 automatic for that build.

Same tooth counts and different diameters doesn't make sense.

On the magnum engines, the CRANK sensor controls ignition timing and reads the notches in the flywheel.

The CAM sensor is in the distributor and controls injector timing.

On the TBI engines it was one sensor in the distributor.

Possibility, have the 3.9 flywheel rebalanced for the 5.2 and have the timing notches added?

I would not run that V6 trans behind a V8. I don't think it'll hold up especially if it's an NV2500 they were weak, even behind the V6.

Trying to get an LA based V6 TBI system to work on a Magnum V8 engine will be tricky, you will be making your own path here. Aside from the ignition issues you mention, the V6 throttle body injectors are too small. It would probably be much easier going megasquirt and using the magnum's stuff instead. It won't care about the flywheel issue if you run it in batch fire and not sequential and it can handle the ignition.

Yea, the crank sensor that reads the tone ring on the flywheel. Me bad.

The 3.9 and the 5.2 are both internally balanced, so as far as balance, they are the same. The 3.9 stuff bolts directly to the 5,2. The only problem is the crank sensor notches in the flywheel. I'll post more about that and what I've read just today. in my next post.

As far as the tooth count on the flywheel, I've looked at so much stuff the last couple of days, I may have that confused as well. Both flywheels use the same starter. There is also some debate as to the actual difference in the actual outside diameter of the flywheel. some locations selling flywheels sat there is a one inch difference, but some sites say there is only a 1/2" difference. The problem is, so much stuff changed between 91 and 95 and there were mechanical differences between the Dakota and the Ram during those years that were no longer different after 97.

I understand the concern about the light duty trans behind the V8. The deal is, I have two of these NV2500 transmissions here. I don't do high rpm clutch drops anymore, and I don't do a lot of hard gear banging anymore. I have fairly narrow regular street tires with pretty poor traction. I'm not too concerned about killing the transmission. If I kill the first one, I suspect I will be a lot more mellow with the 2nd one, but if the dumb kid rises up inside of me and I break the 2nd trans, I will just install a bigger trans, or park the car so I can keep my license. The word it both the NV3500 and the NV4500 both will bolt onto my bell.

As far as being on my own with the TBI or any fuel injection, I've been on my own with this car since 2010. The Ramcharger's Magnum system that is on the motor, along with the engine harness, and the computer are all available to me. I'm not afraid to break down the Magnum harness and see what I need to do to make it work on the coupe. The last Ramcharger listed was in 1999 or 2000. That should have been before all the BS started with the computer monitoring everything. The TBI only had 4 or 6 wires actually spliced into the regular wire harness when I broke it all down. As a side note, the early TBI was used on the late 80s trucks. I suspect bigger injectors are available, but making the TB function on the keg intake could be a challenge.

The problem while I'm sitting here on my chair, is that I really don't know the model year of the Ramcharger. I have just installed a new low pressure 90 EFI fuel pump with a return line on the car, I am a bit concerned if that fuel pump is up to the task.

I have been reading about my flywheel problem. I ran across a video (we all know those are absolutely factual and without errors). The guy was installing an LA 5 speed setup into his 95 V8 Dakota that was an auto trans. He was telling how he heated the town ring on the 3.9 flywheel a couple places so it would expand a bit, and knocked the tone ring off the flywheel. Then he just added the flex plate for a 5.2 on and bolted it between the crankshaft flange and the flywheel, used longer bolts, and torqued the flywheel down. He did state that he needed to raise up the crank sensor from the bell with a couple washers between the sensor and the bell. He said the tone ring on the flex plate sits up about a 1/4" higher then the now removed tone ring from the flywheel. He also stated that if you have a V6 computer in a 94 & newer Dakota (or Ram) the computer, it has active cavities for the #7 and the #8 injector wires already there. He said that if you have a harness you can get two prongs from and place the prongs into the correct cavities, you will have the #7 & #8 injectors functioning correctly.

I'll see if I can link that video. OK, I have no idea how to load a U tube video. The title is "3.9 to 5.2 swap flywheel answers" by Charles Field.

Mopar Action did a v6 to v8 swap on an early Dakota BUT both engines were Magnum style.

Thinking more about modification to a flywheel. Pretty sure the number of notches matches number of cylinders. Possible to fill the undesirable notches and make the needed ones? In other words, get a 3.9 Magnum flywheel and make it fit the 5.2.

Ruderunner, that was pretty much what the guy in the video did with the tone ring on the 3.9 flywheel, he didn't fill the marks, he simply removed the tone ring from the flywheel. He stated that the tone ring is pressed onto the flywheel and if you heat the ring itself, it nearly falls off the flywheel (he said it simply tapped it lightly with a hammer, and it fell off). Once the old tone ring was removed, he just added a V8 automatic trans flex plate between the crankshaft flange and the manual trans flywheel. The V8 auto flex plate has the correct tone ring already attached. Since it too has the one offset mounting bolt, it is automatically in the proper position for the V8. He does recommend that you use slightly longer flywheel attaching bolts because of the added thickness with the flex plate added. He also says you need to space the crank sensor away from the block the thickness of two flat washers at each mounting bolt, between the sensor bracket and the block because of the raised elevation of the tome ring.
I happen to have two 3.9 flywheels here, I'm not afraid to kill one of them, and a new V8 flex plate is $35 on line. I can have one here mid week.

The guy also says that the 6 cylinder computers (I assume he is talking OBD2 here) already have an identified pair of cavities built into them to run a # 7 injector and a # 8 injector. He gives the cavity numbers (I would have to go back and watch the video to remember which two they are). According to him, if you have a couple of matching pins with wire attached, you can seat the pins into the correct cavities in the computer and the other end attached to the injector feed. Then you need to connect the ground wire for # 7 & # 8 injector to the other injectors ground to have the other two injectors to function correctly. For me, that may not apply anyway, my 3.9 is throttle body, and OBD1. I have the wiring and computer available from the 5.2 and is port injected and should be an OBD2 (has the keg intake). I managed to splice the current EFI system into this car, I believe I can handle this upgrade as well (the Ramcharger should be before all the security junk the newer stuff has).

If I can remove the tone ring from the V6 flywheel, and the V8 flex plate (maybe use the current flex plate on the 5.2) sandwiched between the crankshaft flange and the V6 flywheel. I won't have an issue with using the NV2500 5 speed (until it breaks, and I have a 2nd NV2500 trans). At that point, I would probably splice in the Magnum harness and computer to replace the OBD1 that is in the car presently. Then, add the cost of what ever I do with the exhaust (might just be split the exhaust into duels and add glass packs), and maybe a couple wheels (not a requirement, but a desire). I'll probably replace the 5.2 timing chain, and do the plate thing on the bottom of the keg intake and a few new other gaskets, and its still a pretty inexpensive undertaking (lots cheaper then a full start up project). The new tires (which are probably the most expensive single portion of this project, IF I don't have to buy a stand along EFI system) would be coming anyway, the old tires are nearly wore out (have around 50,000 miles on them) and are now 6 years old.

I'm going to be looking deeply into the condition of 5.2 next week. Getting it out of the Ramcharger might be the biggest part of the project.

Didn't get to watch the video so can't comment on that yet.

But, using the flexplate for the tone wheel should work OK. Just watch for proper clutch operation since the flywheel is now deeper into the bellhousing. Starter engagement too but I think there's enough tooth engagement built in.
I wonder if the 5.2 tone ring would fit the 3.9 flywheel?

To clarify what seems to be a misconception, OBD2 didn't come about until 96 or so. Your TBI and early Magnum are both OBD1 and very different systems from each other. OBD2 is mainly a communications protocol and standardized codes that the government imposed on manufacturers.

Gene. The more I read about your possible project and the more I do my own thought process (AKA what I would do) I keep coming up with the same idea. Not that I completely understand all the tech information, that is way above my pay grade and my very limited knowledge, but it seems to me a complicated project, not impossible, just difficult. That opinion comes from me being old and lazy with not that much time left for lengthily projects. Your results will vary of course.

I understand your reasons for using your existing completed car and redoing it to new requirements but I wonder if that is the only way to skin the cat and accomplish what you now would like to have.

Just thinking out loud and also just food for thought with many reasons against it but if I was doing it (and glad I am not) I would start over again and build a brand new project exactly the way you want without some of complications of changing the old one. Drive the old when needed and then sell it later. Just a guess but the time and money might end up being much the same.

I will go back to my room now.

Disagree. He's not talking about going a completely different direction but updating what he's got. Or backdating as the case may be. Most of what is being discussed can be prepared ahead of time and changed over in a weekend.

One thing to emphasize, newer technology has it's own jargon. And that jargon needs to be understood, acronyms have distinct meaning. A CMP is not a CKP.

I know a few old time backyard mechanics and they make me cringe calling throttle body injection systems pressurized carburetor. My supervisor doesn't know a thing about hydraulics but talks fast enough to buffalo management into believing he does.

Old Ray, I have a 49 Dodge pickup that I have rebuilt on a Dakota 4x4 chassis. I just completed that in 2022. The next spring I put this 48 Plymouth business coupe on the market. For a year, no one showed any serious interest in the car. It was priced at what several people in the business told me was a fair price. Then this spring I dropped the price by $4000. I had 2 calls, both offering me less then 1/2 of my lower asking price. I pulled the car off the market and started driving it occasionally. That is what has brought me to this point.

Originally, the car was suppose to be my tribute to the old dirt track cars, but I wanted to drive it on the streets. I also wanted my wife to join me, so some compromises had to be made, which I happily did. In 2018 I had to do a few updates on the car (originally built in 2011), and along with those updates, it gained a few more creature comforts that took it farther away from the original concept then the first batch of compromises took it. Through all of that, my wife and I have enjoyed this car through 27 different states and over 100,000 miles. It has been a great journey, I wouldn't have wanted to do any other way.

Now, the 49 pickup has replaced the coupe as that ride we both enjoy. Since June of 2022, we have already enjoyed driving the 49 pickup more then 25,000 miles, and have covered 9 states. The 49 pickup likely won't see the number of states, or probably not see the number of miles the coupe has seen, we are both older then we were when the coupe hit the road in 2012.

Since it is apparent that the coupe has no current value as it is, and I still rather enjoy hopping in it to run across town, I have determined I needed to take it back closer to what it started life being. Essentially, I taking it from being a V6 to being a V8, adding duel exhaust with glass packs, keeping the same manual trans, and changing the tires & wheels to something more fitting to represent what an old dirt track coupe looked like in the mid 60s. Even at my older, slower pace, this should be able to be done over this winter (the entire 49 pickup build, less the body work and paint, took 11 months). I have some money to use, I have the V8 given to me. I have a car with a sound chassis, modern functioning brakes, and good modern suspension and steering that is already titled, insured, and licensed, none of which would exist with a fresh new build.

The biggest challenge is keeping the current electronic fuel injection and matching up the parts and pieces without spending thousands of dollars. I have built several ground up cars (including this coupe the first time around and my 49 pickup), so this really isn't a completely new experience, its just another twist in the big picture.

Follow along as I shake the cobwebs out of my head, and get this old body of mine busy again. I'm that guy that will spend hours of time trying to make something work (or not), before I will spend a couple hundred dollars to buy someone else's fix.

There is conflicting information concerning the fit of the 5.2 tone ring on the 3.9 flywheel. The guy on the video stated that the 5.2 flex plate clears everything on the 3.9 flywheel, but you have to raise up the crank sensor to clear the larger diameter tone ring. The guy in the video addressed the depth of the starter teeth engagement on the flywheel. He stated that normally, the center of the starter teeth are engaged in the center of the flywheel, with the flex plate added, the flywheel engagement will be towards the end of the starter teeth, but still fully engaged. With the thickness of the flex plate being under an 1/8" of thickness, I would expect and issue with the clutch disengagement should be able to be addressed with the clutch rod adjustment.

The thing that bugs me the most about this deal is everything I read says all the V6 motors have a 13.5" diameter flywheel and the V8 uses a 14.5" diameter flywheel. But from 94 on, the literature states all motors use a 14.5" diameter flywheel (with different tone rings between the V6 and the V8 and a different balance for the 5.9), all use the same bell, the same transmission, and the same starter. One place they state that All V6 have the 13.5" flywheel, but then the same source says the V6 has a 14.5" flywheel from 94 on as well. Wonder why there is confusion?

The OBD1 & OBD2 also brings conflicting info. The full size trucks and the Dakota trucks supposedly have different time lines concerning when things changed. Several locations state that the Magnum motor was introduced in the Dakota line with the 93 model year (if you are buying a rebuilt 3.9, it is either 92 and older, or 93 & newer), but the full sized trucks didn't receive them until 94 (but this Ramcharger that has a 5.2 Magnum is suppose to be a 92 model year). Some literature states that the OBD2 started with the introduction of the Magnum motors, some state 96. I know a 92 Dakota and a 93 Dakota (both were V6) had much different computers and different wiring. The 92 was an LA 3.9. the 93 was a magnum 3.9. The 96 Dakota I have has a different computer and wiring then both the other two, and it is definitely an OBD2, but it is also a 5.2.

The information is so polluted, and the dates are so mixed up, the average guy that was not directly involved can't get a straight answer, and the available information isn't clear and may give to several different answers to the same question.

Since the throttle body injection only has the two injectors in the throttle body, I assume they are batch fire and dump gas into the intake with each notch in the tone ring, as it fires the correct plug according to which notch it passes on the flywheel? If I have a V8 tone ring, won't it still dump the gas and plug fire the correct plug according to the correct notch?

The keg intake doesn't have that look of being too good with the air gas mixture running through it, especially since it injects the fuel very near the intake valve. Are those early port injection motors also a batch fire gas dump with each tone ring notch? As long as I can get the V8 tone ring to work, can I splice all 8 port injectors to the current throttle body injector wires to get all 8 injectors to batch fire and assume the smaller port injectors won't dump as much gas as the two larger injectors for the V6 throttle body? Trying to wrap my simple mind around this.

There's a lot of terminology getting mixed up here. To be clear, OBD2 is a government mandated set of standards for computer communication. It has nothing to do with the engine itself. It applies to all engines across all manufacturers from 96 and up.

Obd1 is just a made up name to differentiate between OBD2 and not OBD2. There's no standards shared by any manufacturers in those Early systems.

In other words, ignore it for now.

Your 3.9 uses an ignition and injection control system that is incompatible with a Magnum engine. There's 2 Magnum control systems, 95 and down and 96 up. I believe the basic engine can use either but the computer and wiring must be from the same system.

Your free Magnum is the Early system . Use the computer and wiring that goes with it. The 3.9 TBI stuff will go in the trash.

As for year discrepancy, the 5.2 Magnum came out a couple years before the 5.9, 91 and 93 respectively. Not sure when the 3.9 changed. But realize there's more changes to the engines themselves than just the induction systems. It was a sea change spread out over a couple years.

The flywheel situation doesn't seem that confusing. From what you say, prior to 94 the v6 and v8 used different flywheels, 94 and up they standardized. I would bet the nv2500 disappeared in 94 so there would be no need for the smaller flywheel.

TBI injection systems basically have the injectors spraying fuel any time the engine is running. Those injectors are not timed to anything other than engine load and rpm. The computer uses rpm, MAP sensor and TPS to determine how much fuel to spray. There's a sensor in the distributor for ignition timing only.

Magnum are multi point fuel injection MPFI system and uses the same inputs as above PLUS engine timing to fire the injectors when an intake valve is open. The computer figures out when a valve is open by comparing the timing notches on the flywheel (for ignition) with the timing notches in the distributor. (For fuel timing)

Along with the MPFI changes, the intake became a "dry" manifold. No fuel passes through it and attempting that will be troublesome at best.

Again, if you want to go Magnum, everything from the TBI system goes to the trash. They are not compatible in any way.