One of the quickest daily driver cars I built a trans for quite a few years back is still running his original torque converter. Its a 97 car with over 145K miles on it, and they are hard miles. Its ran 12.1s at over 114 and lots of 12.3-12.4 runs, all on slicks. The trans has been through hell and back and has never ever had any diff or converter troubles.
Having good home brew fluids helps too . Low 12s/high 11s is about the fastest I intent to build for and outside of helping a few guys out with a race build I wont offer them either, there are other guys to cater to those needs and I focus more on the every day guys running 12s or 13s and up. When I see a stock converter go bad because it was the solely the converters fault I will quit using them, but with hundreds out there and not a one that has came back its an easy choice for me, they work and 0% failure is more than respectable in my eyes. As far as the 245mm converters I dont know how many threads I have read over the years with all the problems. ZZP converters are about the only ones that I have not heard of any issues with and that I have referred people to buy. Mike I have never heard of any problems with the converters you sell either but dont really know anyone using them. I have been talking with a few companies on converter builds, but they will be top end converters no less than $650 like the rwd stuff out there with a good reputation
