OS 21 XM V1 head shims

[Jeremy Linney]

How many head shims are needed in this engine(all stock) for 50-60% nitro usage. Seal kit appears to come with two(different in color) shims. If using both does orientation matter in stack up?

 

[Jeremy Linney]

Never mind, got some help from Grim.

 

[Mike Hughes]

ZERO