I want to fine tune my carbs and I have been led to believe that it's important to know the AFR. I am running a Rover V8 with Weber 500 carbs and megajolt. Does anyone have any ideas on the best way to achieve this? This system needs to be as locost as possible and I have two exhausts!

Edit: I have been searching around and the Innovate DLG-1 would suit me perfectly I think but it's not very locost.

[Edited on 30/4/15 by Irony]

ExtraEFI do a cost effective one, I think it's called the Spartan.