Wanting to rebuild motor but confused...

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DentDimensions

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Picked up a 93 Magnum 360 longblock casting # 53020006
Heads casting # 3418915H

Was told by machinge shop that this combo would not work, however was a running motor before I bought it. Was also told that they are LA heads, also told they were a "J" style head.

I want to build a 450hp streetable motor.

Anyone know what I have and what I can do with what I have???

Confused on the casting numbers, was there ever a factory motor that was a magnum with LA style heads on it???

This is going in a 1974 Dodge Dart Swinger
 
The last years of the LA engine used roller cams, open chamber heads and shaft mounted rocker arms. These engines were throttle body fuel injected but were not called magnums.

The 5.9 magnum came out in 93 so you could have a late LA 5.9. If the engine is a magnum it will have individual rocker arms mounted on pedestals verse the LA where they are all mounted on a shaft. The intake bolts are vertical while the LA intake bolts go into the head perpendicular to the face of the head. The magnum uses a serpentine accessory belt which spins the water pump backwards and the timing cover does not have any provisions for a mechanical fuel pump.

LA heads do not work on magnum blocks (with out a lot of expensive macine work) because the LA heads require oil to the rocker shaft that is provided through a passage in the block and this passage is not there on magnum blocks (but I have heard that some early magnum blocks had the passage).

Hope this helps you identify what you have.
 
Thanks for the information, I actually read some of that in other forums. I was told that from the casting number that this is a Magnum block, the date code is 12/93. Does have one hole on each side of the deck that goes down to the cam bearing. Just wanting to see if I can run LA Heads on this Block, or if it is more feasable to run Magnum heads. Not sure what the cheaper option would be.

I already have a supposed set of LA "J" heads casting # 3418915H.

This motor came out of a 1995 Dodge 3/4 Ton Truck.
 
What I could find shows the block being produced in the 89 - 92 year range and your heads from 71 to 89.
Someone that knows for sure will more then likely chime in and either confirm this or blow it out of the water. Good luck!
 
Thanks for the info, still not clear if I have a LA Block or a Magnum Block. Is there anything I can look at on the flex plate or harmonic balancer to tell me what it is?
 
I do not have any books handy or that may contain numbers for Magnum engine blocks, but, like said above,

IF you have oil holes on the blocks deck going down to the crank, then this is a "LA" style block no matter what the numbers are. Like said above, there has been some blocks that are on the boarder line year machined "LA" style but will have Magnum heads on top. Since the Magnum heads don't care if oil is coming up through the block, only the pushrods, machining the block in the "LA" style doesn't matter. But surley does when it stopped. If stopped to early and the use of LA heads was still on going...well, there be alot of unhappy and dead engines out there.

The nicest thing there about the block is the roller cam set up. GOOD TO GO BUDDY! YEA! Use the LA heads if the oil passage is there since not only do you have them, but switching is simply repurchaseing pasrt you allready have and then rockers pushrods hold downs etc.....
 
Hi, if it´s a magnum engine it should have two tapped holes on the passenger side rear of the block, just behind the cylinder head. These are for the crank position sensor used with EFI.

Michael
 
360duster said:
Hi, if it´s a magnum engine it should have two tapped holes on the passenger side rear of the block, just behind the cylinder head. These are for the crank position sensor used with EFI.

Michael
Click to expand...

Are you sure of that?

The magnums I worked on had a hole in the bell of the trans for the sensor, but hey....
 
the 360 LA roller motors that came with throttle bodies in 88-91 (?) have the mounts for the crank sensor on them also...I got two of them .

you are not going to find LA heads on a magnum block...no way to oil the rocker shafts...

the casting number 53020006 is from a 88-91 360 LA 360 roller motor...just went out and looked at the one that is on the engine stand....
 
You have a late model LA block with roller cam provision. I have the same setup, But I installed magnum heads and rockers. I bought pushrods and roller lifters for a 2001 magnum,they fit and suppy oil through pushrods. installed a comp 280 roller, mopar magnum valve springs, M1, 750 demon, stock crank and rods, Keith Black 168 flat top pistons for compression(under 10 to 1) With the KB pistons, you dont have to deck the block for zero deck quench. Pistons are 10 in the hole. piston to valve clearence is fine, over 150 on the exhaust, more on intake.cloyes db roller time set, melling hv pump and felpro gaskets. my 71 dart finally broke into the 12"s. I will never laugh at a 318 again.
 
rumblefish360 said:
I do not have any books handy or that may contain numbers for Magnum engine blocks, but, like said above,

IF you have oil holes on the blocks deck going down to the crank, then this is a "LA" style block no matter what the numbers are. Like said above, there has been some blocks that are on the boarder line year machined "LA" style but will have Magnum heads on top. Since the Magnum heads don't care if oil is coming up through the block, only the pushrods, machining the block in the "LA" style doesn't matter. But surley does when it stopped. If stopped to early and the use of LA heads was still on going...well, there be alot of unhappy and dead engines out there.

The nicest thing there about the block is the roller cam set up. GOOD TO GO BUDDY! YEA! Use the LA heads if the oil passage is there since not only do you have them, but switching is simply repurchaseing pasrt you allready have and then rockers pushrods hold downs etc.....
Click to expand...

Isn't that roller cam going to allow him the option of a more radical engine with a smoother idle and better vacuum?
 
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