As far as the vacuum canisters,those retard timing all over the place. Not one will match the other.
My friend is an expert in this field as he is an expert on Corvairs,which is where they originated from.
Same person that is a distributer & expert in these J&S knock retard set-ups
http://www.jandssafeguard.com/ ,Highly recommended,but pricey I use on on my Syclone & has saved my engine on more than one occasion..
I have stated before,a vacuum canister cannot hear detonation,but the J&S unit does & retards timing accordingly w/out sacrificing too much performance.
I am a firm beliver in modern electronics to help save/protect your engine from detonation.
Two cents thrown.
MBHD
