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318 LA to 360 Magnum Swap
#1311411
09/27/12 10:15 AM
09/27/12 10:15 AM
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Joined: Feb 2004
Posts: 1,833
Sault Ste. Marie, Ontario, Can...
moparmike1
OP
top fuel
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OP
top fuel
Joined: Feb 2004
Posts: 1,833
Sault Ste. Marie, Ontario, Can...
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I have a tired 1972 318 LA in a 72 B-body (originally a 318/904) that I would like to swap out to a late 90s 360 magnum and keep the 904. I’ve searched the tech articles and forum, have found pieces of information regarding such a swap but not a complete run down so I would like to ask about the following and if I have it right. I’m tried to do this as cost effectively, i.e. cheap, as I can but still being realistic. Engine Mounts – Schumaker’s conversion mounts are the easiest way to handle this. Oil Pan – crate version 360 magnum oil pan and one piece gasket. Camshaft – keeping the stock camshaft but also the mechanical fuel pump so I need the Hughes Engines adaptor, http://www.hughesengines.com/Index/produ...mp;partid=22194to use the eccentric. Timing Chain Cover and Accessories – I’m keeping the timing chain cover and accessories from the 318. First to use the mechanical fuel pump and the 360 I’m looking at doesn’t have any accessories. Intake – Re-drill the magnum heads for an LA 340 intake. Carb – Small block early 70s Thermoquad. Kickdown Linkage – Can use stock 4-barrel linkage with the stock intake, TQ and A904. Exhaust Manifolds – 340 manifolds with Remflex gaskets to take care of the Magnum’s raised ports possibly causing a leak with the manifolds. Flexplate – Get a 96-02 360 Magnum flexplate since it has the weights already. The 904 torque converter is already neutral balanced. 904 – Stock rebuild, nothing out of the ordinary. Starter – Stock mini-starter. Valve Covers – reuse the 318 valve covers to keep the 360 looking stock, period correct, etc. Thanks in advance for any help, Mike.
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Re: 318 LA to 360 Magnum Swap
[Re: moparmike1]
#1311413
09/27/12 11:31 AM
09/27/12 11:31 AM
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Joined: Feb 2003
Posts: 8,671
Andrewh
master
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master
Joined: Feb 2003
Posts: 8,671
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Quote:
Engine Mounts – Schumaker’s conversion mounts are the easiest way to handle this. or you could reuse the 318 mounts and use spacers on the drivers side(I think) to take up the extra space.
Oil Pan – crate version 360 magnum oil pan and one piece gasket.
not the cheapest way, any 360 la pan works, and apparently they make a 1 piece la gasket now. but not sure it is a big deal if you can't find it.
Camshaft – keeping the stock camshaft but also the mechanical fuel pump so I need the Hughes Engines adaptor, http://www.hughesengines.com/Index/produ...mp;partid=22194
to use the eccentric.
Timing Chain Cover and Accessories – I’m keeping the timing chain cover and accessories from the 318. First to use the mechanical fuel pump and the 360 I’m looking at doesn’t have any accessories.
Intake – Re-drill the magnum heads for an LA 340 intake.
unless you already own it, the crosswinds are pretty cheap for carb.
Carb – Small block early 70s Thermoquad.
Kickdown Linkage – Can use stock 4-barrel linkage with the stock intake, TQ and A904.
Exhaust Manifolds – 340 manifolds with Remflex gaskets to take care of the Magnum’s raised ports possibly causing a leak with the manifolds.
durango manifolds worked in an early b for me. should be fine in a later b, should be pretty cheap too, again unless you aready have the manifolds.
Flexplate – Get a 96-02 360 Magnum flexplate since it has the weights already. The 904 torque converter is already neutral balanced.
2 things here. I don't think you can use the stock flex plate since the screws to hold it on are spaced differently than the stock 904 torque converter. in addition, I think you have to hvae a 96 and up magnum to make that work. B&M made one for the 727 and you could slot a hole for the 904, but I never tried, so cannot say.
904 – Stock rebuild, nothing out of the ordinary.
Starter – Stock mini-starter.
Valve Covers – reuse the 318 valve covers to keep the 360 looking stock, period correct, etc.
Thanks in advance for any help,
Mike.
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Re: 318 LA to 360 Magnum Swap
[Re: moparmike1]
#1311415
09/27/12 05:46 PM
09/27/12 05:46 PM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
master
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master
Joined: Dec 2006
Posts: 3,533
Indiana
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Quote:
Timing Chain Cover and Accessories – I’m keeping the timing chain cover and accessories from the 318. First to use the mechanical fuel pump and the 360 I’m looking at doesn’t have any accessories.
Also consider that you need a damper/balancer and it MUST be from a 5.9. 360LA has different balance from Maggie, so don't try to use one of them either. Also, late in the 5.9 run teh damper and lower pulley became a 1-piece assembly (and serpentine, of course).
You could always use a $35 square-block electric pump as you're going carb.
Whatever yu do, teh V-belt and Maggie front accessory drives must almost always be kept intact as a whole system. Mix-match of parts will cause headache. 
Using an LA roller cam was mentioned:
Mags oil the rockers individually thru the rockers, so you must use Mag lifters & hollow pushrods. The LA cam will have 2 oiling holes thru 2 journals, I can't remember if using an LA rolelr in a Mag block causes any trouble, though.
Parts I seek:
driver doorpanel, 65 Sport Fury, prefer black, needs to be 7-8 on 10 scale, might buy set
16" x 6" Dodge truck wheel(s), from early 70s?, takes 9" dogdish - need for a research job so cheaper is better.
69-73 C-body caliper brackets and/or splashields
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Re: 318 LA to 360 Magnum Swap
[Re: BulletBob]
#1311417
09/28/12 08:49 AM
09/28/12 08:49 AM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
master
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master
Joined: Dec 2006
Posts: 3,533
Indiana
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Quote:
How does that cam snout extension fail if the bolt is torqued correctly?
I've used a few of them the first one I bought has almost 100k on it
I wondered that too. Combination of high RPM and higher-ouput fuel pump, maybe? And maybne not torqued properly so teh clamp force between button & cam was low, causing the little key to carry more load? 
Parts I seek:
driver doorpanel, 65 Sport Fury, prefer black, needs to be 7-8 on 10 scale, might buy set
16" x 6" Dodge truck wheel(s), from early 70s?, takes 9" dogdish - need for a research job so cheaper is better.
69-73 C-body caliper brackets and/or splashields
Send a PM.
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Re: 318 LA to 360 Magnum Swap
[Re: warpspeed]
#1311420
09/28/12 11:15 AM
09/28/12 11:15 AM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
master
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master
Joined: Dec 2006
Posts: 3,533
Indiana
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An internally-regulated alternator can't be wired to an external regulator.
The blue wire to the ext regulator is the ign wire and should go to teh new alternator somewhere. The green wire between old alt and old reg can be deleted.
But...
Weren't some of these alts regulated by the engine ECU? Or is that post-Maggie?
Parts I seek:
driver doorpanel, 65 Sport Fury, prefer black, needs to be 7-8 on 10 scale, might buy set
16" x 6" Dodge truck wheel(s), from early 70s?, takes 9" dogdish - need for a research job so cheaper is better.
69-73 C-body caliper brackets and/or splashields
Send a PM.
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Re: 318 LA to 360 Magnum Swap
[Re: warpspeed]
#1311425
09/28/12 03:32 PM
09/28/12 03:32 PM
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Joined: Dec 2006
Posts: 3,533
Indiana
Fury Fan
master
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master
Joined: Dec 2006
Posts: 3,533
Indiana
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EDIT: a few more responses came in while I typed this, not sure if I helped or not.
Not having a schematic for this, we'll need to talk in generalities.
External:
Blue was ign wire, went to alt and Vreg. Green goes from Vreg to alt and turns the alternator field on/off. Mid-60s had 1 field, later ones had 2 fields.
Internal:
Ign wire must go to alternator for reference, then the Ireg switches teh field as needed.
However -
The Mag style is external but triggered by the ECU. Without a schematic, or info from someone who has done it, anything else is just guessing. It could be triggering the alt via + or -, and to teh field or input voltage.
Both:
For both styles the heavy 12-10 ga cable is what is used to keep system voltage up by filling teh battery. That +/- voltage comes across the blue wire and the Reg reviews it again to decide whether to cycle the alt fields.
You might try browsing 'madelectrical' and see if they have further info.
Last edited by Fury Fan; 09/28/12 03:35 PM.
Parts I seek:
driver doorpanel, 65 Sport Fury, prefer black, needs to be 7-8 on 10 scale, might buy set
16" x 6" Dodge truck wheel(s), from early 70s?, takes 9" dogdish - need for a research job so cheaper is better.
69-73 C-body caliper brackets and/or splashields
Send a PM.
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Re: 318 LA to 360 Magnum Swap
[Re: warpspeed]
#1311426
09/28/12 04:22 PM
09/28/12 04:22 PM
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Joined: Feb 2003
Posts: 8,671
Andrewh
master
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master
Joined: Feb 2003
Posts: 8,671
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Quote:
Andrew, that would be the better way, maybe? But, I have the 99 magnum engine and it's water pump, and alternator bracket with the single serpentine system. Therefore, I used the 99 alternator that fits that bracket system. That is an internally controlled alternator. Now the question is whether it needs the cpu or can get by with just the wiring, going to it with the electronic box that mounts on the top of the alternator. Maybe that is all that I need to make it work.
I think you need to show a part number or picture of this 99 internal alt. Mine is a 2000 mag and it was externally regulated. So I am not sure which alt you have, and have never heard of one like that.
For mine, I used the plug coming out and wired it like I would any dual field alt. 2 wires came out. one went to ground, the other went to my vr output.
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