Magnum 360 rebuild help

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65MagnumFish

65MagnumFish

65MagnumFish
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Zeeland, MI
My situation is that I purchased a 360 magnum with 70,000 miles on it. I really want to get the car on the road but wondered how far do I need to rebuild the motor to make it reliable. I am planning on running carburetor but feel that if I start by changing the cam it becomes a slippery slope. I would appreciate what advice my fellow a body brothers have.
 
If it only has 70,000 miles then it’s got another 150000 to go. Leave it alone unless you know that there is a problem.

Jake
 
xLURKxDOGx said:
If it only has 70,000 miles then it’s got another 150000 to go. Leave it alone unless you know that there is a problem.

Jake
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I would think that even at stock (sort of) it should move a 65 barracuda. Figure I’d throw some headers on it with an edy air gap. Suppose I could do the cam stuff later if need be.
 
My plan on my 5.9 magnum was to keep the short block as is and put some EQ heads on it....but I had a trashed crankshaft and bearings were not great. Project got a little out of control when I did the 408 kit. You plan on only spending so much for your project and you spend 3 to 4 times that. Oh well, Rod

IMG_4666.JPG
 
Just do the obvious, compression check and document the numbers. If that checks out good, check and change what seals and gaskets have been obviously seeping, maybe a fresh performance water pump (a good radiator upgrade is not a bad idea either, small engine compartment, thin casting magnum heads), quality timing chain upgrade, intake, headers, if I was planning on a cam I would go ahead and do it while I had it out. It's easier to check for coil bind and other issues and change springs (if your grind requires it) if it's on an engine stand. Ignition upgrade, distributor recurve. Like xLurkxDogx said, at 70,000 miles the internals are going to be fine, the incidentals I would do because it probably has sat more than been ran. Check your oil pan gaskets and crank seals, you don't want to have to change those in the car.
 
If you don't know the history of the engine, and did not get to hear it run, I would suggest you should check all the rod bearings. You'll need to install a car style oil pan and pickup anyway, so they'll be accessible. Many of these have no problems in the shortblock components, but if it has a problem why not catch it now. I have had a few of these apart that had one rod bearing and crank journal torn up. You don't want to find that after getting it all installed.
Once you are sure it's all good, go for the camshaft upgrade and matching valve springs. You can keep the factory roller lifters, but factory valve springs definitely won't work well with a camshaft upgrade.
 
Some of the advice on here is so good that I’d give it a thumbs up, check mark, and thanks at the same time... Kudos, Bobzilla, I badly overlooked the truck pan.
 
Robert Corrigan said:
My situation is that I purchased a 360 magnum with 70,000 miles on it. I really want to get the car on the road but wondered how far do I need to rebuild the motor to make it reliable. I am planning on running carburetor but feel that if I start by changing the cam it becomes a slippery slope. I would appreciate what advice my fellow a body brothers have.
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I bought one with over 90k on it and besides the heads being cracked and being able to see daylight through some of the closed valves :D the bottom end looked great.
So good in fact that I didn't even put new bearings in it, and the cylinders still had really visible cross hatching.
The bottom end looked like it had 10k on it, so I got a set of EQ heads, Roller chain, a cam and new springs and built it as an LA motor.
Doesn't use a drop of oil between changes and runs great.

MagnumswapLA.jpg
 
TrailBeast said:
I bought one with over 90k on it and besides the heads being cracked and being able to see daylight through some of the closed valves :D the bottom end looked great.
So good in fact that I didn't even put new bearings in it, and the cylinders still had really visible cross hatching.
The bottom end looked like it had 10k on it, so I got a set of EQ heads, Roller chain, a cam and new springs and built it as an LA motor.
Doesn't use a drop of oil between changes and runs great.

View attachment 1715285158
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Your engine compartment looks like **** man.:D
 
Awesome input. This was exactly what I was looking for. I have the intake off and the valley is very clean. Came out of a 150 van. Anyone try the Chinese air gap clone for an intake? Great news on the factory lifters. I was looking at the hughs stuff but seems there’s a lot of options.
 
With the chineese intakes its a 50 /50 chance you have of getting them to seal. From what I have seen most tend to go with the Eddie on for the magnum carb motors.
 
Years back, people used to adapt LA intakes to magnum by cutting thick wall aluminum tubing that an intake bolt will fit into at a vertical angle to standard LA heads and welding them to the intake, then drilling the holes vertical in the flange. I would view it as being only practical if you can do it yourself and have a favorite LA intake to do it with, like a regular performer RPM. The real go/no-go gauge would be the opinions of the Magnum experts on the boards, as I have not gotten to attempt it myself. Would make for some interesting tunnel ram or single plane combinations, though.
 
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If magnum 360 heads weren’t so crack prone, I’d try out TM-5 magnum 318 with a drag race cam and 4.56 gears just for the fun of it. Too bad I don't have a set of ported Eddy aluminum magnum heads milled down to about 52cc's laying around.
 
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Robert Corrigan said:
Awesome input. This was exactly what I was looking for. I have the intake off and the valley is very clean. Came out of a 150 van. Anyone try the Chinese air gap clone for an intake? Great news on the factory lifters. I was looking at the hughs stuff but seems there’s a lot of options.
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My uncle used one of the air gap clones on the 5.2 magnum that he installed in his 70 Dodge truck . The engine is 100 stock except the intake and my uncle said he can't believe how much power and better it runs, compared to the LA 318 2 barrel engine.
 
So let’s say I go get a Hugh’s cam. Do I need to get new lifters, springs and rockers? I’m afraid if I go nuts on buying parts it’s going to slow my project done date. Also would a 7 1/4 sure grip hold up to the upgrades I mentioned?
 
If you're on a budget, just check out the rod bearings, main bearings 1-4, and if all looks good you are probably in business. Used factory lifters are more reliable than anything you can buy new and they even work with bigger camshafts. Just make sure the roller wheels spin smoothly by hand while they are out.
Factory rocker arms can stay if in good shape. Check for scuffing in the pushrod cups though.
Pretty much everyone will agree the stock factory and replacement springs are not good enough, unless you keep the rpm very low. Install the Hughes spring and retainer kit even if keeping the stock camshaft.
With the 7 1/4 rear end, you decide. I broke one in a body with stock 318 and lots of burnouts. Also had one last the life of Diplomat behind a slant six.
 
The magnum I ended up using was only $200 when I bought it, but it came with the car pan and pickup. I bought it as a core.
Tore it down, the cylinders looked excellent, the heads as usual each one was cracked, but the crank and bearings were rough.
It needed turned, it came out of a 250 van, so my guess is worked hard, and run low on oil.
Rebuilt with a crank turned, new set of eddy heads which also needed guide work.
KB107 std pistons, bottom end balanced, and a small comp roller cam, it is a huge improvement over the the old 318 LA that was in my power wagon.
I also added a MP duel plane intake and a 625 street demon carb.
My dad who bought a 78 power wagon, new with a 360 said to me when he drove it the engine is exceptional compared to his old truck.
 
Awesome help. That was what I was looking for. Bobzilla really helped me with the valve spring information. Thanks.
 
Robert Corrigan said:
My situation is that I purchased a 360 magnum with 70,000 miles on it. I really want to get the car on the road but wondered how far do I need to rebuild the motor to make it reliable. I am planning on running carburetor but feel that if I start by changing the cam it becomes a slippery slope. I would appreciate what advice my fellow a body brothers have.
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Wondered also which water pump would work well? I don’t want Chinese stuff and the magnum is going in a 65 barracuda. Thought there might be an issue with the direction the pump might angle at?
 
Seems that everything is chinese today. I bought a set of SKF bearings, made in china says the label on the box...
 
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