As said, make sure the VS you have has a .060" restriction in the return nipple. It's a fuel filter also.

I have been running them on both my cars and only use them, no other filters other than the sock in the fuel tank. Just like the factory did on 440 6paks and hemis.
My 340 has had one since 2003 and over 15K miles and my 440 since 2005 with a lot less miles. My 340 has been run in all conditions like 110 degrees in Vegas and 32 degrees and 95 degrees(was there twice) at 14100 feet in Colorado. I'm sold on them with a return line. Properly installed they prevent vapor lock. Both of my fuel pumps are mechanical. They would help even more with a electric pump.
Drove my 340 car all weekend and even to work this morning, it was frosty this morning.