How bad are by manifolds ?

[GRR]

I have taken the manifolds and risers off my VP 431
I have no idea when they were last replaced but they look pretty good to me.

Is there any way I can actually tell how much life they have in them ?

 

[AndieMac]

Sand-blast as much of the internal waterways as possible (not too savage) and compressed air clean out, or acid bath.