LA vs Magnum pistons

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ragtopfury

ragtopfury

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So we've got a complete 74 360 that I had picked up for Josh's 73 Sport "Fred". Planning a stock bore refresh, with a little 340-ish cam.

I have a local guy wanting to sell me a set of pistons/rods from a 5.9 magnum.

Are the magnum slugs and rods compatible? If so, any benefit?

I ask, because I do not know.
 
The Magnum rods are different on the small end somehow. Either thicker or thinner than LA rods. Also, the compression height may be a little different, as the Magnum blocks have a shorter deck height than the LA. That said, as long as they are Magnum pistons to match the rods they should fit and work fine.
 
The rods im not sure about but rusty is right on about the pistons. They have a different compression height. If I recall they are shorter. So they would be lower compression in an LA
 
You will need the crank to match the rods for balance, the last few 5.9 I disassembled the piston was down aprox .050 from the deck. la 360 I think is .020 taller deck.
 
Magnum rods have a thinner small end but since they’re on Magnum pistons…. Moot point….

Regardless…. It’s not a move I’d make.

IMO, you’re much better off getting a set of KB-107’s or Speed Pro C116HP pistons and new rods if the OEM stock units need a bit of work. These pistons sit about .020 below deck (they did on my 360 block) this will provide a easy streetable pump gas friendly mill at approximately 9.5-1 with a thin head gasket and stock 72 cc heads. With Edelbrock heads it’ll be approximately 10.5-1.
 
They say the rods are as strong as 340 rods, but I don’t believe it as I heard they are powder metal.
 
ch1ll said:
They say the rods are as strong as 340 rods, but I don’t believe it as I heard they are powder metal.
Click to expand...
Not the Magnum rods. The GEN 3 hemi rods are, but not the Magnum rods.
 
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