3.910 + a few lines

With 280 D 474 L cam 4 speed and 373 rear gears in my Demon can I use 1 7/8" TTI step headers?

Hi Bubblegum .
Welcome to the site .
Your question popped up in the middle of an "engine overhaul" conversation, so it likely was ignored as a mistake, because it didn't fit the conversation.
If you start on this page/link, you can find a conversation on exhaust, down in the "technical" section .
For A Bodies Only Mopar Forum
ask the question there.- it then will be answered by knowledgeable folks there .
https://www.forabodiesonly.com/mopar/forums/mopar-exhaust-systems.55/.Good luck,
lotsa helpful, knowledgeable folks here .