I don't buy it, was his torque converter matched to his application? Really matched? Plus its a 518, they take more power to run, just like the 727. On that link, all I see is a ridiculously colored sales pitch. Lets let more chime in on the subject. Still doing my 42RH swap without batting an eyelash.
I just hate to tell you this, but the 518 and the 500 use the same overdrive. That is where the problem is. Sure a 904 has a bit less internal inertia to overcome than a 727.... So you can say the same about the 500 vs. the 518.
I started off with the stock converter.... Is was fine... Worked ok... So the initial flash was much less... It was a dog out of the hole.... No problem I thought... I'll get a good converter, and that will fix it....well, it helped.... But it certainly didn't overcome the problem. I was running a VIPER converter... Yes matched to my application, I am far from new to this stuff!!! I was told that the 727 has 5 lbs. of weight to compare to 33 lbs. of the 518, specifically. Ok... Let's say a 904 has ZERO INTERNAL INERTIA, you still have 28 in the OD. Look.... No one wanted to make this combo work more than ME!!! Hey.... Performance may not be all that important to some people.... I just happen to fall into a different category. I want my setup to be as RIGHT, AND FAST, as possible, and this transmission was THE PROBLEM.....PERIOD!! FWIW. Todd