AdamR
Big Member
Has anyone used these yet ? Im wonde how much needs to be milled to use them with closed chambered heads and if you would use them again ?
Kb356 pistons
- Thread starter AdamR
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dgc333
Well-Known Member
Adam, Those are step/dish pistons for 4" stroker motors (408 cid). With the step at zero deck you will be less than 10:1 assuming 64cc for a magnum had.
Also, If you are using LA rods you will have to have the small end narrowed to 1" to fit the piston. It was for this reason I stayed away from the step/dish pistons that KB has for magnum heads, I didn't want to add cost to reworking stock rods or have to machine the brand new Eagle rods that I wound up purchasing.
If you are thinking of going this way I recently picked up a complete magnum engine that I will sell you the rods for $50 for the set if you are considering going that way.
Also, If you are using LA rods you will have to have the small end narrowed to 1" to fit the piston. It was for this reason I stayed away from the step/dish pistons that KB has for magnum heads, I didn't want to add cost to reworking stock rods or have to machine the brand new Eagle rods that I wound up purchasing.
If you are thinking of going this way I recently picked up a complete magnum engine that I will sell you the rods for $50 for the set if you are considering going that way.
AdamR
Big Member
I have a 5.2 I could rob the rods out of but I want this motor to be atleast 10:1 so those pistons wont work.
dgc333
Well-Known Member
If you were to use a head gasket with a 0.020" compressed thickness or machined the heads to get the chambers to 60cc you would be just over 10:1.
The dish volume in those pistons is 23.5 cc, a typical Fel-Pro head gasket has a 4.180 bore and a compressed thickness of 0.039 and the magnum heads have a chamber volume of approx 64cc.
Here is a slick calculator that you can play around with different specs to work out the compression ratio you want.
http://www.csgnetwork.com/compcalc.html
The dish volume in those pistons is 23.5 cc, a typical Fel-Pro head gasket has a 4.180 bore and a compressed thickness of 0.039 and the magnum heads have a chamber volume of approx 64cc.
Here is a slick calculator that you can play around with different specs to work out the compression ratio you want.
http://www.csgnetwork.com/compcalc.html
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