KB190 360 standard pistons
What compression will these be with a stock cc J head with .053 gasket? Will these be above deck with a non milled block? Thanks. Kim
As you know, these aren't mine but, maybe this will help the seller...
Being that they have a slight dome/pop-up (0.080"), they will extend above deck. Looking at KB web page, the compression should be in the 10.5-11 area, depending on the actual cc of your J heads.
KB Automotive Hyper - Chrysler 360 / 5.9 - KB190
Compression Ratio: 62-11.8, 64-11.5, 68-10.9, 72-10.5
Using a standard LA deck height (9.600"), I come up with the following...
1/2 of the stroke = 1.79"
Rod length = 6.123"
Compression ht = 1.675"
TOTAL = 9.588"
...plus pop-up = 0.080"
Calc above deck = 0.068" (9.588 + 0.080 - 9.600)
When I run compression calculations using -1.2cc from KB description, 69cc heads, and assuming a Felpro 1000 gasket (~8.8cc), I come up with 10.75 to 1 compression. Anyway, hope that helps.
