Have you ever heard of D & P Torque Converters?

A quick Google search lead to a company called D & P products in Sacramento. There was only one review and it was not a good one.
I always found that most transmission shops had very little or no knowledge on performance converters. They never asked the right questions other than what stall are you looking for. They seldom if ever,asked about what had been done to the engine, what gear ratio was in the rear end, tire size, etc. All questions that need to be asked so you can get the RIGHT CONVERTER for your application. This is not a knock on transmission shops, but most transmission shops while knowledgeable on how to fix your transmission, very few know much about high performance.
My advise to you would be to contact one of the many performance converter builders and find out what they say will best suit your setup. Price wise, you get what you pay for. Good converters with good internal components are not the least expensive for sure, but the poorly made ones are of course price attractive. A well made high stall will typically be : furnace brazed, will have 3 sets of torington bearings in it, have a hardened steel hub, srag assembly built to withstand more abuse, HD mounting pads, electronically balanced etc. When you go that extra mile for extreme horsepower and you'll get anti-ballooning plates, custom made billet steel front cover, diode style sprag, and other items designed for high performance use.