First off to Dave:
I understand but the comment "sell that shit and start over" bugged me and implied I sold the guy a faulty part. I was not even aware of any deal with you for your trans and this is the first I've heard of it.
Now for the subject at hand - Frank (the OP) does not have a lot of experience, and quite frankly, doesn't know if he was spinning or not from inside the car. He has crap other than what he mentioned so it is no surprise to me his 60's were worse than he expected launching off the brake.
Having said that, Paul - you are 100% correct also - that new converter is the unknown. It was certainly put together by TCS for a 700 rwhp car and also after knowing their previous one was slipping to oblivion so I concur that the converter is probably way too tight for his set-up.
I also gave him the Ultimate Converter 10" TC. He sent that back to Ultimate to get refreshed. That converter was also for a 700 rwhp set-up but Frank also bought my Whipple and is going to be putting it on the car with a 3.25" pulley making close to 700 so why even fuck with the converter right now, Frank - is my question?
Since you are going to put the whipple on - don't worry about the trans and converter right now. Put the whipple on, put on the 10" from Ultimate when it comes back - go from there is my advice.
It makes no sense to dial it in for your car now when you are going to put the 3.4 on the car. Follow the advice I gave you and just shore in and dial your suspension now in prep for the whipple. At 700, your suspension should be your #1 priority right now and see where you stand with the trans after it's back married to the same power plant that it was set up for.