5.9 Magnum block vs 360 LA block....

1WildRT said
I'm looking at building a small block for a friend.. Currently he has a 340, it needs everything & we're talking about going to a stroker kit.... The one thought I have is using a 5.9/360 roller block rather than the 340.... Let the resto types buy the 340... So, what I'm finding is the 89-92 360 roller blocks are getting harder to find but 5.9's are everywhere....

We already have LA style heads & rockers.. I'm wanting to put a 360 stroker kit in a 5.9 block... About the only thing I keep reading about that's different is the 5.9 has a shorter deck height... So I searched for the stock deck height spec... 5.9 Magnum spec is 9.58, 360 LA spec is 9.59.... .010 difference.... I've decked plenty of blocks .020-.030 so .010 is of no concern.... So I'm here to ask if there's something else I need to be aware of, what's gonna bite me on the butt?

Edit, yeah, I know about the oil passage, got that covered..

I appreciate everyone's input...

1WildRT said
That right there answered one of my questions... I was wondering about the oil pan/timing cover cause I will want the early timing cover & obviously will have the Magnum rear main cap... Which I wasn't sure if it was the same as a regular 360 cap or not.... Thanks for that tidbit... I'll be checking out the Magnum Swap link..

I have a line on a 96 5.9 block which from what I've read should have the oil passages... I also have a Bridgeport so drilling a couple oil holes isn't much of an issue...

Magnum blocks have their own oil filter adapter plate, different from an LA. Do not interchange them. Just use the parts off the donor Magnum block and it is not an issue.

Old style Chrysler starter will usually interfere with the Magnum engine block. Use a mini starter from the Magnum trucks and it is not an issue.

All Magnums, 5.9 and 5.2, use the same oil pan gasket, and you can install the car 360 LA oil pans with a Magnum gasket by using some silicone in the gaps left by the LA pan at the front. I had to do this on mine because a Milodon oil pan was not shaped correctly and the holes for the little nubs on the front LA seal were way off. The Magnum gasket actually fit better, the LA pan has extra "steps" the Magnum gasket will not seal. Just fill those little voids with silicone.

If using a Magnum block with LA oiling holes or drilling the two missing holes on a later Magnum block make sure the camshaft is drilled for LA oiling. Some Magnum spec performance camshafts do not have the long snout on the front requiring an adapter, but some also do not have the LA oil holes drilled in the journals. Not an issue if using pushrod oiling lifters, pushrods, and rocker arms or when using a proper LA camshaft and the holes are present in the journals and the block.

Some of this was already covered and some was not. If I have not forgot any details, the rest is just treating it like an LA.