71 Dart 410 stroker ..

Ok...playing musical cars....get this one out of the trailer..test transbrake....no creeping....tried 4 times...no creeping.....was wondering since everything was cold if the thicker tranny fluid was causing it not to creep.....Saturday it is up on jackstands....let it run and get trans warmed up....if i had to pull the trans...i was going to swap out to newer converter that is sitting in the box...a $1300 converter is surely got to be faster then a 250 dollar converter bought back in 1983.......