I will mention this as I trashed a 700r4 when I installed my rebuilt engine in my Blazer when I was in high school. Are you sure that the torque converter was installed properly before you bolted it to the flywheel. If not, you trashed the front pump in your transmission, and it will knock. When I did this, the transmission lasted exactly 100 miles. I was almost hoping that the knock was coming from my engine because I had a balanced and decked 350 on the engine stand, but my dad made me rebuild the 305 that was in the Blazer.

Phil

Never hold your farts in. They travel up your spine and into your brain...that is where crappy ideas come from.