I have 4" from turbo, would like to run straight pipe when not towing, and run a muffler when towing, anybody know if they make a y pipe with a manual flap in them.

http://www.jcwhitney.com/product.jhtml?CATID=5199&BQ=jcw2


OR


http://www.mccordcg.com/mpp/mpp.htm



This is sort of what you want but its the wrong size but maybe you can inquire about a larger size. I know I've seen them before for mounting behind headers with 4" collectors but I can't seem to find them now. If I do I will post back.Edited by: stretch