No. I installed a 10% OD pulley with the shorter belt and still had substantial belt slip during dyno pulls. I estimated that the pull was short at least 25 hp because of the slippage. I even saw smoke comming from the pulley during the pull and decided to end any further tuning until I fixed the problem.
Research has resulted in purchasing new tensioner springs from Magnum Powers or Super Coupe Performance. These should eliminate the problem.
Good luck.