Forged 340 Crank in a 5.9 Magnum

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KS Hcode

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I have looked and looked and cannot find the answer. Probably because I am too new around here...

I have a forged 340 crank, forged Hbeam rods and some JE SRP standard bore (4.04) pistons. Since it is next to impossible for me to find a good 340 block near me, I was wondering how feasible it would be to drop the 340 rotating assembly into a 5.9 magnum with the appropriate crank bearing spacers?

If I wasn't going 4 speed then I would not bother with the 340 crank. Also I know the wrist pin locations are different on the pistons so I could not just plug in the rods and pistons.... Unless I am missing something.

T I A,
Dustin
 
And you MIGHT have to mill the pistons, the magnum block has a shorter deck height than the LA
 
KS Hcode said:
I have looked and looked and cannot find the answer. Probably because I am too new around here...

I have a forged 340 crank, forged Hbeam rods and some JE SRP standard bore (4.04) pistons. Since it is next to impossible for me to find a good 340 block near me, I was wondering how feasible it would be to drop the 340 rotating assembly into a 5.9 magnum with the appropriate crank bearing spacers?

If I wasn't going 4 speed then I would not bother with the 340 crank. Also I know the wrist pin locations are different on the pistons so I could not just plug in the rods and pistons.... Unless I am missing something.

T I A,
Dustin
Click to expand...
What is the compression height of your pistons, or the part number?
I have a set of SRP pistons I plan to use in a Magnum block. I think they are part number 34796 with 1.670” compression height. We still had room to deck the block to get close to zero deck with these.

Search for threads on four speed swaps with Magnum 360 engines. I know there was few asking about that. As long as you are not using factory Magnum fuel injection a four speed swap should not be too bad.
 
Bob,

Yes my SRP's are 1.670 CH. I plan on going the 6pack route as that is what my dad had in his car. Hoping I can make it all work out the way I have it in my head.
 
Bobzilla said:
What is the compression height of your pistons, or the part number?
I have a set of SRP pistons I plan to use in a Magnum block. I think they are part number 34796 with 1.670” compression height. We still had room to deck the block to get close to zero deck with these.

Search for threads on four speed swaps with Magnum 360 engines. I know there was few asking about that. As long as you are not using factory Magnum fuel injection a four speed swap should not be too bad.
Click to expand...
Were you using the factory 360 crank?
 
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