If you lock the stock converter, than probably not as the locked stocker might be 0-1% slippage in 3rd where the PTC could be around 4%. But considering the PTC will dramatically reduce your 60ft time, it will more than make up for the possible 1 or 2 MPH loss on the top end, if you lock the stocker that is.
The stock converter is not efficient left unlocked, similar to the Precision etc. I think your initial pass was unlocked so the PTC would destroy in this situation.
Either way, you need a converter and the 7 blade compressor wheels are also not as quick at spooling up as their 6 blade brothers so that's not helping you much here either.