Get yourself an AFR meter!

Reading through some of the posts here on carb tuning, I recognize a lot of issues I've had my self with regards to tuning carbs, be it for improved performance and response , or simply trying to sort out problems like bad idle, flat-spots, bogging etc..

For the amateur, like my self, the problem is that we just don't know what's going on. We are left with seat-of-the-pants, and trying to interpret all sorts of indirect telltales which can often be symptoms of many different things.

The only way to properly tune a carb to work optimally at ALL engine conditions, is to run an engine on a dynamometer with an exaust gas analyzer and fuel-flow measurement equipment.

That was untill inexpensive wide-band lambda sensors and Air-to-fuel meters became available.

Now, I'm running a fuel,injection system on my 318 (megasquirt controller buildt froma kit and DIY hardware), but I had tuning issues I really struggled to get arround. The narrow band lamda sensor could onlu tell me if I was lean or rich relative to Stochiometric.

I then upgraded to a wide-band lambda sensor twhich allows me to read the actuall air-to-fuel ratio.

Suddenly I could actually see what was going on!

were those cold starting problems due to lean or rich? Did I need to adjust the cranking-fuel, or was it the afterstart enrichment that was out?

Full throttle, or nearly full throttle; was I bordering on lean or was I over-rich thereby burning excess fuel and loosing power?

Suddenly I was able to do exact diagnostics and true fine tuning whilst driving.

Obviously, you will get the benefit of this even if you are running a carb.
And I would say that even if not directly cheap, the price to pay is really small compared to the advantages, not to mention just the fun of actually being able to get somewhere with your tuning and realize the full potential of your engine! :)

I would say that trying to tune your carb or efi without a wide-band sensor/ AFR meter is like trying to set the ignition without a strobe-light; you can sort of do it, but you will never be spot on and you risk doing (costly) mistakes.

The only physical modification required is to weld in a bung for the sensor somewhere in the exhaust system, the rest is a simple wiring excersise.

The one important thing is to make sure the exhaust system doesn't have any leaks as this could cause false readings.

My best spent money so far, and the best advice I can give to anybody here.

Good luck! :)