After some core shift issues I have experenced with the mopar 340 siamese replacement block P5153478AB, I have located a 318 Magnum P5153579 with a finished bore of 3.910". Before I outlay more cash I was wondering if anyone has played with/or has more info on this P/N block. Am I correct in saying that all 59 deg siamese blocks are of the same casting and just finished differently in the bore size and in the main tunnel for 360 Mag block. If this is the case one would think that there would be plenty of material to play with if mopar state max bore 4.220?????
And can you use standard LA oiling to the heads with this P/N block?

Thanks in advance
Macka

I am not 100 % sure , but I seem to recall that the magnum blocks are finished for pushrod oiling , so there are no oil passages to the head.
As for taking one to 4.220" , if you are going that big on any small block , you probably want to sonic check it.......but I don't think it is possible with anything less than the siamese bore blocks.........which ain't the factory replacement blocks.

From what I read, this block is siamese bore and can be bored to 4.220. You would want to sonic check it though. I believe the magnum designation means it has the tops of the lifter bores machined for the lifter links and the spider tray. It may or may not have oiling through the block for the shaft rocker setup. I also read that it needs a 318/340 oil pan, not a magnum318/360 oil pan.

I would definately sonic any block first. I was mainly after someone who has had one of these and has had it sonic checked so I have something to comare with.
I'm after 4.125 bore with the possibility of 4.155 or 4.185 down the track. I have a 340 oil pan which is good.

I had my '99 360 block sonic checked before it was bored.... and they pretty much told me that with boost - 4.030 was really pushing it. All I know about them is what my machinist told me (for what it's worth) ... He thinks if anybody wants to go 4.220 on a Magnum block - they will have to install 8 sleeves.

Once again - I am NOT an expert - just a consumer that's passing along info second-hand.

Sorry - I didn't catch the R3 part.
That does make a slight difference.

I wish I hade 1... or 10.

Alan,

Copied from your link.......

MOPAR 5.2L 318 "LA" MAGNUM RACE BLOCK 3.91" Finished Bore

ID:P5153579


Magnum and "LA" Blocks are designed for general high performance use and entry level racing.
Block, Cast Iron, Race, 5.2L Magnum/318 "LA", Siamesebore, 3.910" Finished Bore

Retail Price: $3335.00
Online Price: $3011.45

Full Description

Features:
· Ready for assembly without the need for any additional machining
· Bored and honed to standard bore size
· Camshaft Bearings and freeze plugs installed in block
· Hardware kit included
· Ductile Iron Main Caps with ARP bolts (four-bolt on the center three caps)
· Dual motor mounts with "LA" and Magnum mounts
(must use late 1970s 318 mount for left side)
· Heavy duty casting with thicker deck and bore walls
· Works with all stock-style engine components
· P5153452 & P5153579 work with Magnum stock-style
Hydraulic Roller Camshafts (requires tappet retainer kit P5155275)
· Not recommended for use with aftermarket tie bar style mechanical
roller tappets
· Siamese Bore (all except P5007552AB) - allows up to 4.220" bore size
· Standard deck height - 9.600"
· Setup for wet sump oiling system with oil drain holes in the valley

******* · Magnum blocks can also be used for "LA" applications with dual
oiling system provisions (LA oil passages to heads or Magnum oiling
through pushrods, and flat tappet or hydraulic roller cams)*********


· MPI provisions for Magnum crank trigger
· 59° Tappet Bore - works with all stock-style cylinder heads and camshafts
· P5153579 requires use of 318/340 "LA" oil pan (stock 5.2L Magnum oil pan will
not fit)

It states in the link you posted they are good for both oiling systems.....

The reason I mentioned the oil pan is I have a Milodon in the shed that suits 318/340.


My main cause of concern is cylinder wall thickness considering they cost 3000 plus freight half way around the world.....once bitten twice shy!

Macka




·

Are those blocks pre-drilled to oil thru the block or are they factory set to pushrod only oiling and you need to drill the passageway? The next time I pull my engine to freshen, I may drill mine to oil thru the block to open the door for using LA style heads on it. Could actually let it oil both ways as long as it didn't affect the way it oils everything else. I have been wanting to do that but it's still as strong as it was brand new even after going into it's 6th racing season without haveing the block or rotating assembly touched. I did change cams last year alone with Hughes shaft mount marnum style rockers. Other than that, it never even had a valvecover pulled off. Thats durability at its finest! I even thing the older it gets, the faster it goes. I love the magnum stuff.

For those who missed it, the OP gave a casting number that started with a "P". That means it is a Mopar Performance piece, not a stock block out of a pickup.

R.

Sorry guys, I should have been a little clearer in my original post. I'm actually looking at the Mopar block from the Mopar catalog not the OE block.......

As a side note, regarding this little tidbit:
Hydraulic Roller Camshafts (requires tappet retainer kit P5155275)

If you want to use that kit, try to see if it exists. Not sure what your plans are regarding lifters.

Good luck,
Ran

on early Magnum blocks (94-95), both oiling systems are in the block, so you can use LA heads with their shaft oiling system, or Magnum style trough the pushrods...

Dan

Buy the block through an engine builder who can sonic test it for you before they ship it over to Aus. Might cost you a little more, but atleast you will know what you are getting. You could try Brian at IMM engines in California.

Thats what I think I'll do this time round.