Magnum Swap with Carb

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JDMopar said:
You need to use the 5.9 Magnum flex plate as you planned, but you will have to open up 1 hole in the flex plate to bolt to your existing converter. If you take the flex plate off the magnum motor, and bolt it to the converter in the truck, 3 bolts will line right up. You will then see what little bit needs to be hogged out of that 4th hole. Others may disagree, but I kinda think a 750 cfm carb is too big for a 360. Sounds like a good swap, so good luck.
Click to expand...

If he leaves it stock,. I agree with your carburetor assessment.
 
The 300 HP (gross) crate 360 is the 245 net HP stock magnum 5.9
 
The 300 hp crate is a stock truck long block, cam and all, with a intake swap. The 380 hp crate is the same long block with a single plane intake, a bigger cam, and different valve springs.
 
Why do they not recommend using the factory MPI or AC if it is just a stock motor?
I wanted to use one in my Dakota but didn't because of this statement.
 
moparmarks said:
Why do they not recommend using the factory MPI or AC if it is just a stock motor?
I wanted to use one in my Dakota but didn't because of this statement.
Click to expand...
Because it's being sold as a "performance" replacement engine. The 300 hp version could easily use the factory efi and a/c. The 380 horse version could not
 
93ragtop said:
FWIW I think we need to be careful comparing hp rated in net or gross.
I believe the crate 300hp engine is a gross rating....
The say, 2000 ram 5.9 240?HP is net rating....
Assuming the crate motor was installed with factory magnum exhaust manifolds, and the only real changes is an alum. aftermarket intake, small 4bbl. and electronic ignition, in reality, the hp is going to be much closer.
Click to expand...
True, it is a gross rating. Just basic changes on the engine. The typical beginner bolt on hot rod parts.

Jadaharabi said:
Could you look through that catalog and find out the part number for the valve springs that was used in that 380 horse motor?
Click to expand...
Does it suck that you can’t get the MP bump stick anymore?

MoparLeo said:
The book says it "dyno tested" 300+ . Gross or net ???
Click to expand...
At the flywheel.
RustyRatRod said:
If he leaves it stock,. I agree with your carburetor assessment.
Click to expand...
What I did at the bottom.....

YY1 said:
The 300 HP (gross) crate 360 is the 245 net HP stock magnum 5.9
Click to expand...
replicaracer43 said:
The 300 hp crate is a stock truck long block, cam and all, with a intake swap. The 380 hp crate is the same long block with a single plane intake, a bigger cam, and different valve springs.
Click to expand...
Pretty cool what a few bolt on parts do huh?
moparmarks said:
Why do they not recommend using the factory MPI or AC if it is just a stock motor?
I wanted to use one in my Dakota but didn't because of this statement.
Click to expand...
Good question. I wonder if it is an intake manifold fitting issue? That it interferes with the A/C bracket? Magnum style A/C issue? I think that’s it. Not so much the LA brackets.

@Haney I plucked out a ‘00, Durango 5.9 for my ‘79 Magnum. Backed it with a 727 & 3.55 gears on 27 inch tires. What I did to the engine was;

Installed a RPM & a 600 AFB carb w/a ‘72 trap door air cleaner housing a K&N filter.
Junk yard distributor fired by a MP Chrome box.
Hooker Super Competition 1-3/4 Headers into a 2-1/2 exhaust to the bumper. The 1-5/8 provides a little more torque for this particular application and I just used what I had on hand.

The car is a good bit lighter, just under 3800lbs. vs what ever your truck weighs in at. So when it comes to a cam, I would keep it small for the added torque your looking for. You will not need a big lift. Just another 10*’s of duration is all you’ll need.

If this was my situation that your in, besides the above of what I did, I would certainly select a Hyd. roller cam for a simple replacement swap. The cam itself is a tick over $300, but you reuse everything else. (Perhaps not the valve springs....) Though a new timing chain and chain tensioner would also come with the cam since your all ready there. You might as well!

I found the (‘00) Magnum in my (‘79) Magnum a really nice power plant. Very torquey &
with good HP for a strictly street bound daily driver.
The 600 cfm carb was IMO an excellent match with really good pedal response and road manors. I’m sure a 750 would work. But I have seen no need for it unless I would be spending more time upstairs in the rpm range. Which is done early with the factory cam.

I didn’t have the flex plate. I used a B&M flex plate to mate to the neutral balance converter. I also used Lokar cables for the throttle and trans kick down.
 
Pretty sure the 380 could to, unless the design of the intake prevented it, which may also be the issue with the 300 version.
 
The 380 used the MP single plane. I never noticed an A/C set up with that intake.
 
Edelbrock made 2 dual plain manifolds with the same part number. One has the bosses for the factory a/c and one doesn't. I also have a MI single plain manifold with the bosses.
Also their ratings are with 1-5/8" headers and 750 carb.
 
I checked into this cause I want to put the factory Magnum a/c, alt, and belt setup on my 5.9 in my Dart. My MI dual plain doesn't have the bosses needed the mount the factory brackets.
 
There ya go! Thanks Mark. I figured that was the case.
 
Still think this was misleading of them. You could put the kagger intake on it and that would have everything for the factory MPI and A/C.
 
Perhaps... the factory / MP will make such statements to avoid things. It’s easier on there wallet to print a disclaimer rather than defend a frivolous law suits from dumb asses.
 
↑
Could you look through that catalog and find out the part number for the valve springs that was used in that 380 horse motor?

Does it suck that you can’t get the MP bump stick anymore?


I don't know if it sucks or not. I already have a 512 lift roller that I need springs for.
 
Hummm, I wonder if the valve spring is also in the MP book so you can find out the pressures of them. Or just call someone. Grab an aftermarket PAC spring.
 
PAC beehives would be my choice, should be something available in the pressures required for the cam.
 
rumblefish360 said:
True, it is a gross rating. Just basic changes on the engine. The typical beginner bolt on hot rod parts.


Does it suck that you can’t get the MP bump stick anymore?


At the flywheel.

What I did at the bottom.....



Pretty cool what a few bolt on parts do huh?

Good question. I wonder if it is an intake manifold fitting issue? That it interferes with the A/C bracket? Magnum style A/C issue? I think that’s it. Not so much the LA brackets.

@Haney I plucked out a ‘00, Durango 5.9 for my ‘79 Magnum. Backed it with a 727 & 3.55 gears on 27 inch tires. What I did to the engine was;

Installed a RPM & a 600 AFB carb w/a ‘72 trap door air cleaner housing a K&N filter.
Junk yard distributor fired by a MP Chrome box.
Hooker Super Competition 1-3/4 Headers into a 2-1/2 exhaust to the bumper. The 1-5/8 provides a little more torque for this particular application and I just used what I had on hand.

The car is a good bit lighter, just under 3800lbs. vs what ever your truck weighs in at. So when it comes to a cam, I would keep it small for the added torque your looking for. You will not need a big lift. Just another 10*’s of duration is all you’ll need.

If this was my situation that your in, besides the above of what I did, I would certainly select a Hyd. roller cam for a simple replacement swap. The cam itself is a tick over $300, but you reuse everything else. (Perhaps not the valve springs....) Though a new timing chain and chain tensioner would also come with the cam since your all ready there. You might as well!

I found the (‘00) Magnum in my (‘79) Magnum a really nice power plant. Very torquey &
with good HP for a strictly street bound daily driver.
The 600 cfm carb was IMO an excellent match with really good pedal response and road manors. I’m sure a 750 would work. But I have seen no need for it unless I would be spending more time upstairs in the rpm range. Which is done early with the factory cam.

I didn’t have the flex plate. I used a B&M flex plate to mate to the neutral balance converter. I also used Lokar cables for the throttle and trans kick down.
Click to expand...

Great first hand info! Thank you @rumblefish360 !
 
Stock 5.2 Magnum: Duration: 251In./264Ex. Lift: .432"In/ .432"Ex Cam centerline 113*

Stock 5.9 Magnum: Duration: 249In./269Ex. Lift: .410"In/ .417"Ex Cam centerline 109*
 
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