[daveshilling]

20,000 miles ain't bad... I could definitely just get a $5 cap and see how it runs I guess. It wouldn't be a considerable effort to run a return line after the fact if that fails. I probably wont even drive this truck 20,000 miles in 5-10 years.

I have a 2003 5.3. I've seen posts on LS1Tech and havent found anything definitive about fitment, although I've seen some folks saying they swapped out for returnless rails and had to make custom brackets and such.

LS1Nova, I applaud your consistency, I found a post from 2012 where you recommended running a return, both here and on LS1Tech!

I couldn't find anything definitive saying what rails will fit... flexfuel rails apparently will, but then i need to deal with new longer injectors, and TBSS rails were mentioned but they cost more than $90. Pick n pulls out here are picked and pulled before I get there, so it looks like I try the $5 cap. If it sucks eggs, I do the $90 return line.