I watched flebay for a while and got my LM1 box cheap (like $10). Then got the sensor and cables new from innovate.

Then watched ebay again, and got the logging add-on thing pretty cheap.

Then to make it really useful, I built my own manifold vacuum gauge and ran that into the logging port. Now it logs AFR/RPM/Manifold vacuum, so you can actually see how the AFR changes with changes in throttle position.

Then I converted to electronic ignition and fixed all of the driveability issues I thought were fuel related