5.9 Magnum exhaust/intake combo help

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67CudaBob

67CudaBob

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I picked up a low mileage 1999 5.9 that is very clean. My plan is to drop it in my 1967 Dart GT ragtop for street cruising purposes and daily driver purposes, but with a bit of attitude when I need it.

Here is the data:

I do not plan to bore the block or change heads at this time.

I am looking at an exhaust manifold combo of a 340 driver side and 360 passenger side (machined to 2-1/4" to match the 340) (from what I have read, I will not have enough horsepower to benefit significantly from the additional cost and potential headaches that headers bring)

I have a brand new Eddy 1406 (600 cfm) carb on my 273 right now that I would like to reuse if it makes sense.

I have an 8-3/4 with 3.55 or 3.23 sure grip that will eventually go in. I plan to run a 904 with perhaps a mild stall that matches the power.


1. Is the exhaust manifold plan above good for my planned setup? I doubt it is not enough exhaust, but is it too much?

2. if I go with the exhaust plan above, what would be your intake recommendation for this?

3. if I go with the exhaust plan above, and the ideal intake to match, is my Eddy 600 enough carb?

Thank you ahead of time - this is my first time doing a swap and putting a package together and I have been reading a lot and have a lot more to read and really appreciate all of your knowledge and experience.
 
Well, there's basically 3 intakes for the Magnum. M1 dual plane, RPM (& the knock off's) & the M1 single. If your cam upgrade doesn't warrant the RPM, then the M1 dual will do. A 600 cfm is excellent for street duty. While many will argue for more.....
If you can look for the early magnum exhaust manifolds, do so since they have (IIRC) 2-1/4 exhaust ports. For a melo cammed 360 & dual plane, 2-1/4 dual exhaust will work just fine. Just make it efficient.
 
Those Magnum logs should provide plenty of clearance in a 67. Youl have to rethink your head pipes as they are nowhere close to the LA positions.
 
From how you describe your intended usage, why not use the factory injection? Waaayyy better mpg, throttle response etc.

Funny thing, we have a 67 GT vert that while it will end up with overdrive etc, we decided to go ahead and drop a 5.9 out of a Durango using the factory injection, larger cam and just minor engine mods. We planned to do this soon just to show how easy this is to do with the Tanks Inc FI tank and prebuilt harness. The 67 found us with a newly rebuilt but knocking 318 and fresh 904. Thought we could do a thread of what should be a couple of weekends swap.
 
magnummopar said:
From how you describe your intended usage, why not use the factory injection? Waaayyy better mpg, throttle response etc.

Funny thing, we have a 67 GT vert that while it will end up with overdrive etc, we decided to go ahead and drop a 5.9 out of a Durango using the factory injection, larger cam and just minor engine mods. We planned to do this soon just to show how easy this is to do with the Tanks Inc FI tank and prebuilt harness. The 67 found us with a newly rebuilt but knocking 318 and fresh 904. Thought we could do a thread of what should be a couple of weekends swap.
Click to expand...

I bought the motor without the EFI/ECU (they were gone already), and I had a great new carb -so being my first swap, and keeping costs down, I was nervous about taking on an aftermarket EFI and getting in way over my head. I will be very interested to follow your thread - as EFI may be something I do down the road.
 
Hey Bob. How much cam are you thinking?
And what tire size?
 
rumblefish360 said:
Hey Bob. How much cam are you thinking?
And what tire size?
Click to expand...

I was not planning to swap cams at this time - though I must admit I am contemplating it as I am sure if I don't I will wish I did. So let's say, stock to mild.

Tires (for now) on my 7-1/4 small bolt are (i think) only 225/70/14

when I change out to the 8-3/4 big bolt, I am not certain what tire size yet.
 
FWIW, according to the MP catalog, the M1 dual plane is a idle to 5600 power band.
We know the RPM is a 1500 - 6500 rpm range
The M1 single is a oddly listed at 2600 - 6600. I say this because I also have the W5 version of that intake and it is listed as a 2600 - 7000 power band. Considering this intake is said to be an upgraded copy of the stella Bolley Stip Dominator that also has that M5 power band or better, I don't know why or see where the stock headed version gets shorter in it's rpm range.

But there ya have it.
 
Rob, the stock head port its bolting onto probably ductates its useabke powerband. Look at a std strip dominator then a w2 strip dominator with its larger ports, i get it says 7k too. Fwiw i ran a w2 Strip dominator on LA X head 340 and it ran fine with a 284/484 MP cam, mismatched ports and all. I got the intake in a straight trade for a performer...still think I came out ahead.
 
Pista, I agree to a point. I'll just say it is amazing what some people do and make power and/or go fast. We have here a stock port cruiser, then the M1 dual would get my nod.

I'll be using the RPM on my Magnum with a mildly upgraded cam and a little converter w/3.55's on a 27 inch tire. Even the stock cam that's in the '99 Magnum now works very well.
 
$179 to upgrade to RT grind plus pushrods at $99 will make 300+ verses the stock .397" lift turd stick.
If you converted to Fi, I would go factory mopar, parts are super cheap and it works a lot better than the aftermarket stuff at 2-3x price.
 
Potential hijack alert- but might benefit the OP...

I have 2000 Dakota R/T as my daily.

I have a dealership takeout 2000 5.9 from a Durango (rod knock).

Are these motors identical?

I've never heard of an "R/T" cam.

Also, why would you need new pushrods on a roller cam motor?
 
Whatever you do, upgrade the valve springs.

The springs in it are for low-redline (my 5.2 Dakota is something like 5200 rpm iirc) and the motor had a nice fuel cutoff rev limiter before the efi was removed.

Without the efi and with better intake exhaust, it will easily outrun the oem valve springs. This is why my dart is crippled right now!
 
jos51700 said:
Whatever you do, upgrade the valve springs.

The springs in it are for low-redline (my 5.2 Dakota is something like 5200 rpm iirc) and the motor had a nice fuel cutoff rev limiter before the efi was removed.

Without the efi and with better intake exhaust, it will easily outrun the oem valve springs. This is why my dart is crippled right now!
Click to expand...

The stock valve springs are fine to .450" lift, the 5.2 has .440" lift from factory. 5.9 RT has .455" . You only need springs if you go over .460"-.470" Lift.

I wound the piss out of my 5.2 in my Wrangler with .440" cam for 5-6 years without any issues, it saw 6K on numerous occasions as well as towing 2000# boat through the mountains of Oregon at 65-70.

There is no "nice fuel cutoff rev limiter" on any Magnum MPFI system. There is a rev limiter built into PCM but it cuts timing not fuel and its over 6500 rpm which can easily be raised during flashing. Same for top speed cutoff.
 
YY1 said:
Potential hijack alert- but might benefit the OP...

I have 2000 Dakota R/T as my daily.

I have a dealership takeout 2000 5.9 from a Durango (rod knock).

Are these motors identical?

I've never heard of an "R/T" cam.

Also, why would you need new pushrods on a roller cam motor?
Click to expand...

The RT version of the 5.9 Magnum had a larger cam, .455" vs .397", other than that the 5.9 had 1.88" intake valves up until 2000. The RT came with 1.92" like the 5.2.

I assumed since the OP doesnt want to swap heads or take short block apart that meant there were budget restrictions, which would lead me to recommend a re ground cam for $179 vs a new cam for $379. The reground cam will need longer pushrods.

Or, he could simply use a 5.2 cam for free if he can find one.

My point was about getting rid of the 5.9 cam....
 
magnummopar said:
The RT version of the 5.9 Magnum had a larger cam, .455" vs .397"
Click to expand...

Always heard the Dakota R/T and Ram 5.9's were identical. MP sold an R/T cam, but like the R/T heads, they were never used on the showroom Dakota R/T. Not arguing that there never was an R/T cam, only saying that I don't believe the factory put them in the trucks on the lots.

magnummopar said:
the 5.9 had 1.88" intake valves up until 2000. The RT came with 1.92" like the 5.2.
Click to expand...

:banghead:
 
I had also asked on one of the FxBO forums if magnum heads were identical between 5.2 and 5.9, and was told they were.

So, are there three magnum cams and two head versions?
 
YY1 said:
I had also asked on one of the FxBO forums if magnum heads were identical between 5.2 and 5.9, and was told they were.

So, are there three magnum cams and two head versions?
Click to expand...

Still waiting on confirmation that there is an 1.88 valve Magnum head. I've never seen one, but I don't have them laying around either.

Far as I understand, there is only one OE assembly line head for the 5.2 and 5.9. In 1992, the 318 became the 5.2 Magnum, but the 360 remained in it's TBI state and did have a different head and 1.88 valves. In 1993, the 5.9 rolled out as a Magnum, with the same heads as the 5.2 and 1.92 valves. I would accept proof otherwise, just haven't seen it yet.

There are a multiple of Magnum cams, depending on year and engine size. My comment was only that the Dakota R/T didn't get a different cam than a similar year Ram (or whatever) with a 5.9.

Mopar Performance sold an R/T cam, but it never came in a truck on the showroom floor. Same deal with the R/T heads, they exist, but they are completely aftermarket from MP and were not stock on the Dakota R/T.

The 5.9 in the Dakota R/T was no different than any other 5.9 of the same year, other than it was in a Dakota.
 
YY1 said:
Potential hijack alert- but might benefit the OP...

I have 2000 Dakota R/T as my daily.

I have a dealership takeout 2000 5.9 from a Durango (rod knock).

Are these motors identical?

I've never heard of an "R/T" cam.

Also, why would you need new pushrods on a roller cam motor?
Click to expand...
Yes, they are the same.
There is a R/T cam but it is a MP aftermarket cam.

Stock 5.9 cam (not 300hp crate)-
Lift- .410/.417
Duration- 249/269

R/T cam P5249549 (discontinued)
Lift- .458/.467
Duration- 260/264
 
DionR and LeoDart,
I am not willing to argue with you guys about this again, YOU ARE RIGHT, I LIED, the cams are all the same, valves are all the same, hell, the 5.2 and 5.9 are identical in every way, just different fender badges on the trucks. They just retard the timing on the ones labeled 5.9 to make you get worse mileage and more torque. I have also never taken 100 magnums apart, owned a Dodge Dakota/Durango/Ram performance shop for 20 years, installed 60 magnums in Wranglers since 1999 nor ever been a Mopar Performance Dealer. Have never built 200+ MPFI harnesses and I damn sure dont know jack about fuel injection. I also dont own BackwoodsOffroad.com or magnummopar.com

OP, DionR and LeoDart know the "real" deal with Magnum engines, listen up, I am done....
 
magnummopar said:
DionR and LeoDart,
I am not willing to argue with you guys about this again, YOU ARE RIGHT, I LIED, the cams are all the same, valves are all the same, hell, the 5.2 and 5.9 are identical in every way, just different fender badges on the trucks. They just retard the timing on the ones labeled 5.9 to make you get worse mileage and more torque. I have also never taken 100 magnums apart, owned a Dodge Dakota/Durango/Ram performance shop for 20 years, installed 60 magnums in Wranglers since 1999 nor ever been a Mopar Performance Dealer. Have never built 200+ MPFI harnesses and I damn sure dont know jack about fuel injection. I also dont own BackwoodsOffroad.com or magnummopar.com

OP, DionR and LeoDart know the "real" deal with Magnum engines, listen up, I am done....
Click to expand...

I was afraid you might take it like that. I really was trying to present it in such a way as to say that it was my understanding, but that I was willing to listen to proof otherwise. I wasn't trying to poke at you, only share what I've understood.

I understand and agree that you have a wealth of knowledge and experience, much more than I do, in a variety of areas, and am in no way trying to minimize that. But it doesn't make you perfect, nor all knowing, and I have to say you are the first guy I had ever heard say the 5.9 had a 1.88 valve. You pointed out one website and sure enough he says the same thing, but when everything else I have ever read or seen says otherwise, and when someone else looks in the parts books he has and they only list one valve size available, it just leaves me a little doubtful. I am more than willing to entertain some proof otherwise, and even refrained from using some childish remark about still waiting, because I know your time is valuable and you will get to it when time allows and parts are accessible. Besides, I don't see this as a hill to die on and even if we never agree, you won't be the first person, nor the last, that I haven't agreed with.

It appears that I have really rubbed you the wrong way, since we have only butted heads about the valve size once before and never over the cam. It really hasn't been my intent to annoy you. My apologies.
 
Part of the problem is that there is so much bad info out there. Like I said, the Dakota guys know this but we are not on for dakotas only so, I will have a pre 2000 to take apart, just might take a bit. I just picked up another 5.9 but it in a 2000 Durango so that wont work. Lets just agree to disagree until I get some photos of Elvis holding a 1.88 valve magnum head.

I did look in the Mopar Performance book, "Magnum Engines", long out of print and it lists cam specs for 5.9 that change with the same years as I said they changed valve size, they also list 1.88 to 2000 and have 1.88 and 1.92 both listed for valve size in 2000....I will see if I can find the time to post it. But pretty much the same as I already have.

The RT was rated at 275 hp and has a different computer than the regular 5.9. 30 hp on a pcm flash would be huge on a 245 hp engine.
 
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