la318 roller cam and magnum heads help

cowtipper

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Okay guys, money is tight so lets not get crazy. Plus I like my lil 318. Anyways, I need to pull my heads due to valve seals "I know they can be done without removing heads" but its cold and why not clean and check valves. So here is my question, I have a magnum 318 with a bad block but heads were just redone. What would be my issues in using the magnum heads considering my lifters appear to be oil through "pics added" . I have honestly searched high and low for an honest answer and everyone is all over. Can I just get a quick run down on what to expect. Thanks ahead guys
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AMC Diplomat

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Even roller 318s oil through the head and rocker arm assembly. I've seen people on the interwebs who say they have put Magnum heads on a 318, but it is a giant waste of time and money to make it work. Just save up and by a 5.9 Magnum from a junkyard, get a used intake and carb, and smoke the tires. Or if you're really cheap, grab another 318. They're like $100
 

Mikes5thAve

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Do some digging thru old posts at moparts. There was a lot of parts swapping between engines going on years ago and loads of info there.
 

kkritsilas

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There will be new pushrods required, both for length, and to allow oil through lifters to work properly. There are few, smaller, consideration which I am probably glossing over. The best source of information, if they are still around, is the magnumswaps website (just google/do a web search on it). You may want to have the heads inspected for cracks between the valves, and establish that, cracked or not, they are good to use. You may also end up needing a new intake, or redrill the intake port holes to accommodates the Magnum's intake port slanted bolts, vs. straight intake port bolts of the LA 318 heads. This is all covered on the magnumswaps web site.
 

Duke5A

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This swap used to be a lot easier years ago. At the least you're going to need:

- An intake. Either the Edelbrock Air-Gap manifold for Magnum motors, or the Chinese piece of shit copy Crosswind (if it's still being made) that is drilled for both LA and Magnum intake patterns.

- Check your lifters in the LA 318 to see if they have provisions for oiling through the pushrod. If not, new lifters are needed.

- You'll need to measure pushrod length and get the appropriate length rods with holes for pushrod oiling.

Another thing to consider is valve springs. If you're running an aftermarket cam the Magnum head will need to the spring seat machined for anything over .525" lift or you'll run into coil bind.
 

brotherGood

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Even roller 318s oil through the head and rocker arm assembly. I've seen people on the interwebs who say they have put Magnum heads on a 318, but it is a giant waste of time and money to make it work. Just save up and by a 5.9 Magnum from a junkyard, get a used intake and carb, and smoke the tires. Or if you're really cheap, grab another 318. They're like $100
As one who put magnum heads on a 318..its is not a waste of time.

Sure, a 5.9 would be better, but A. Hes already got the 318 heads. B. There's more to swap over if you swap to a 5.9. C. (Prefaced..I dont like bench racing) the combo I had was stupid cheap, and took an 18 second car down to where it was expected to be in the 13s/rock bottom 14s. All for heads, cam/lifters & intake.

@OP. Going off of memory, I ran factory heads/springs/etc..shim gaskets (.027 thickness IIRC), oil thru pushrods (7.625 I believe), AMC lifters, Summit 6900 cam. The knock off intakes have improved immensely in quality, but I ran an M1 Magnum Dual Plane (obsolete part). Beyond that, your basic 4bbl/electronic ignition swap and the engine is done.

Down the road, I also swapped a SG 3.55 gear in, and before Pops sold the car he had the transmission rebuilt with a higher stall converter. I drove it with the new converter for about 200 feet (didn't have brakes as Pops let it sit and it rusted a line) and it was extremely rowdy.

..yes. I miss it sometimes.. lol
 

brotherGood

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I was out in the garage and remembered I had a couple spare pushrods in a bucket from when I did this swap..so I snapped a picture of one that has the sizing.

I also went back through some archives and found the links I was given.

Summit Racing SUM-1457650 Summit Racing™ Chromoly Pushrods | Summit Racing

Sealed Power HT2011 Sealed Power Hydraulic Lifters | Summit Racing

Summit Racing SUM-6900 Summit Racing™ Classic Camshafts | Summit Racing

Mr. Gasket 1121G Mr. Gasket Head Gaskets | Summit Racing

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