S.U.R.&R. KP1200 Fuel line kit

[JAKA]

Just bought this kit to make the fuel lines for my 5.3 swap. This is going in my 86 K10 using a gas tank and sender for an 87 Blazer. Fuel system is the return style. This kit has the fittings that screw onto the sender. My concern is the I.D. of the return side fitting looks really small. Has anybody had any experience with this kit? I was wondering if this might cause a restriction or not? Only want to do the fuel lines once, hopefully. Thanks for any input.