5.9L Magnum Swap

[superstock74]

Anyone on here really familiar with the Magnum small blocks?
I plan to swap all my LA 360 parts over to a 360 Magnum (MP Cast Valve covers, Intake, headers, pullies ETC) so it will basically look like a LA engine in the car.

My issue is with the valve springs and camshafts. I've read that the valve spring are junk and don't offer much more lift then the factory cam .432" (5.2 Magnum cam spec Int.). Has any one changed out springs? did you have to machine the valve guides or other head work?

 

[PettyBlue72]

The intake for a magnum 360 mounts differently than an LA intake so your stock LA intake will not work with the magnum heads. The magnum uses a reverse flow water pump so you will have to swap the LA water pump onto the Magnum in order to use the LA pullies. I also don't think LA headers are a direct bolt on to a magnum motor and the valve covers bolt on differently as well. I am not to familiar with the valve springs and cams but since the bottom end of a 360 magnum is basically the same as an LA 360 and the performance advantages of a magnum 360 really come from the heads I think you would be better off just rebuilding the bottom end of the LA 360, rebuilding the 360 magnum heads and swapping them onto the LA motor. BTW 360 magnum heads are proned to cracking around the valve guides and most used magnum heads are junk. There are companies that sell new magnum casting heads.

I hope this helps,
Joe

 

[pjc360]

The la360 hedders will work on a magnum 360, they are no different. The valve covers from an la360 can be put on a 360 magnum but it's pointless to do that because the magnum valve covers have 8 bolt holes and the la have 4. So the magnum valve covers seal up a lot better preventing leaks. The intatke from a la360 won't fit on a magnum. Also the magnum is balanced differently then a la360, so if your running an automatic you need to ether balance the torque converter to the magnum spec or buy a balanced flex plate for the magnum. The magnum engines have much better heads then the la360's much better pistons and higher compression ratio. The magnum engine is a lot better then the la360 in stock form and is worth the swap imo.

 

[superstock74]

Thanks guys! I think its just cheaper to buy new EQ head the LA intake bolt pattern. I want to run the magnum because of the roller camshaft, I can run cheap oil instead of 50$ jugs of diesel oil with the ZDDP. With the Roller cam i can get a higher lift with lower duration so a bit more ponies. I've been reading a lot about the stock heads and to really get a decent camshaft you've got to machine the valve spring seats, then check the installed height and a few other things... so doing that at the machine shop is the price of assembled new heads with higher lift valve springs and better castings.

The balancing is always tricky but i've got the weight kit from MP and i'll just runt he stock magnum 5.9L flex plate and dampner. (old LA360 weights need to be removed for the magnum weights on the TC). The idea of this whole swap is to just basically have a cheap, reliable 360hp motor i can beat on and not have to worry about. The LA valve covers are cast MP wrinkle ones so i really want to keep them because of the price they cost and also it makes the motor look like a LA for a bit longer.

 

[rumblefish360]

The 5 bolt LA MP valve covers work no problem. Get a thick gasket for the cover.
The LA heads are better heads. Not the other way around. The LA heads also port out waaaayyyy better.

To use a roller cam in an LA, talk to the cam company you order from and ask them to make the cam for use with a standard oil pump drive so you will not have to purchase and replace the bronze oil pump drive.

Many Magnums also have LA mounts on the side in addition to the Magnum mounts.

Crosswinds has a dual bolt hole mounting intake that is basically a Edelbrock RPM rip off. You can use this intake on a LA or Magnum engine. It looks like an RPM air gap.

Now remember that the cam on a Magnum is shorter (no snout on the cam for the fuel pump eccentric) this means that bolting on the LA stuff MAY require some tricks since the timing cover is thinner.

Did I miss anything?

 

[rumblefish360]

Oh, go to FABO and ask this question as well. I know there are a couple of fellas that have done this.

 

[superstock74]

@rumblefish360 - Thanks, I'm running the crosswinds intake right now on my LA360. Ya the magnums have a short snout but Hughes engines sells the extension kit so you can use the mechanical fuel pump. I would keep the LA block, but to switch to roller is again a late model block or 600$ for lifters, new push rods, new cam. I have a magnum already that ran great in my truck and looks fine inside, so just replace the heads and put in a cam and be done with it.