THe difference is negligible. Since a dyno samples RPM, there's automatic correction for gear ratio changes, but the difference is that numerically higher gears generate more friction. The difference won't be more than 5hp between the biggest gear changes, so 3.42 to 3.73 probably won't change your rwhp in any noticeable way.
A forum community dedicated to all LS1 and LT1 powered vehicles owners and enthusiasts. Come join the discussion about performance, specs, builds, conversions, swaps, modifications, troubleshooting, maintenance, and more!