I am installing a ls1 into a 91 camaro and I want to use the stock fuel lines coming from the engine bay so my idea is a 14mm and and a 16mm an -6 fitting into a -6 tee will this work or does the return have to be smaller then the feed line?

 

feed line is 3/8, return line is 5/16

 

Feed and return can be -6 without issue. Biggest hurdle is converting from return style (stock) to the LS1's returnless system

 

yes I was going to use a 6an tee fitting to connect the 2 and the one to go to the fuel rail.