I'm installing an Autometer wideband AFR guage and am looking at locations for the sensor. Can the sensor be mounted just after the cat or does it have to be between the manifold and the cat? Anyone?
Before the cat. If you have long tubes, in the collector is a good spot. If not, you just need it before the cat but after the "collector" on shorties. You need to get all of the exhaust from all of the primaries on that side so that you get an accurate reading. After the cat and your reading will be way off. There is usually a bung already there if they are aftermarket, though.
Your right. It does. But I think I remember a discussion on a tuning forum that the optimum is 24"s or around that from the exhaust port on the rear most cylinder.