I would get the lockup issue fixed and try it with the stock converter, with 3.73's and torque multiplication of an auto trans. my guess would be you will be quite happy with it.TC stall rating is not only variable with car weight but also engine torque,my guess is your engine makes much more torque than any engine that came stock with a 700R4.If you do decide to go with a looser converter make sure to upgrade trans cooling if you haven't already.Remember the old redneck stall converters the Vega?