What your describing just doesn't sound right for the continental converter. When you punch it it should jump to 2800 instantly and throw you back in your seat. It should have no effect on top end pull. Even below that RPM with light throttle it should couple up pretty tight.

I run the 13" in my car and my brother has the 10" in his GTO. I bought mine from Cliff Ruggles and he strongly recommended that I put new clutch pacs in my th400 with 4L80E clutch pacs. I really didn't want to spend the money but was glad I did as the tranny shop found that my tranny was really shot. I'm sure it had mostly to do with the TCI street fighter converter that I ran in a very heavy 77 GP.

So this goes back to what was/is the condition of the tranny before you installed the new Torq converter?

FWIW I run the stump puller in a 455 and still plan to move to 3:08 gears (currenty 3:36 gears) and SD performance recomended the 13" and Cliff was really pushing that I go with the 10". Since I had a 2800 stall before I really miss it when I launch. I did notice with the 13" converter over the TCI that there was a 200 to 300 rpm difference.

Anyway I would be more inclined to think that the tranny may need freshened up. The cheapest and first step I would take is changing the tranny filter. I know personly that I clogged mine before the 4L80E clutch pacs in the old build in a very short amount of time when it was in my GP.