Tom,
it sounds like your converter might not be that efficient as it could be.
What brand torque converter did you end up installing?
I think there are a few tricks you can do to the trans to help with the slashy/slippery shifts.
Up to a certain stall,you can use a standard trans,but after about 2600-2800 stall range ,some people recommend higher trans oil pressure,.501 valve,& other things.plus a shift kit always helps. I am not a tranny expert,but my friend is.
If you can hold the brake pedal,,, really mash on it & try to build up boost,what rpm does it go to before the wheels start breaking loose? That should tell you approx stall.
The trick thing to do on Syclones & Typhoons is to lockup the torque converter as soon as it shifts into second gear.
It droped my ET .2-.3 tenths, & about 3 MPH.
The 4.3 V-6 in my truck is just a torquey engine that cannot rev @ all,you really do not need to go more than 4500-4800 max RPM
Here are the V-4.3 cyl head flow tests numbers.
BOTH sets of numbers are with 2.02 and 1.60 valves.
Stock heads have 1.94" intake 1.50" exhaust.
before, intake: 65,133,163,174,178
before, exhaust: 51,102,131,139,141
Pretty weak,,,,cam is like .370 lift.173 degrees duration @ .050
