I'm switching gears & picking up a 95 LT1 next weekend w/ factory aluminum heads, Lloyd Elliot cam, 58mm TB, corvette rails w/ Aeroquip regulator, etc, etc. My stock tank is already sumped in the rear w/ the Competition Engineering sump. I also have a new stock sender/pickup installed for the fuel gauge.

My questions are:

What is a good external pump? Power is guesstimated around 375hp but I would like to eventually add a supercharger so want to build a fuel system capable of supporting up to 5-550hp. Was eyeing up the Aeroquip A1000 but think it may be overkill. Also think the 10AN fittings are overkill as I read that 3/8" is adequate for high-horsepower engines. Walbro also makes an inline filter that's 225lph w/ 6AN inlet/outlet for $125 which is more budget friendly. Also, how close to the tank should the pump be mounted?

Fuel line size? From what I've read it seems 3/8" (6AN) is plenty?

Read conflicting info about the return line...is the line in the stock pick-up sufficient or should I create a 3/8" return?

Fuel Filter recommendations: I see 10, 40, and 100 micron filters...which is the best? I'm guessing 100 since it will block finer particles that could clog injectors?

Given your planned HP levels, 3/8" supply and return lines should be fine. Connecting the return into the stock 5/16" sending unit should work too. Walbro makes a 255 l/h external pump that Holley sells as part of their 900 cfm throttle body kits. It will support over 500 hp. Mount as close to the tank as possible. It's typically recommended to mount the pump below the fuel level, but some have been installed above the tank and work fine. Napa sells a 3/8" barb 10 micron fuel filter, p/n 3482 that Holley includes in some of their fuel injection kits. Include some sort of course screen (100 micron) on the inlet of the pump to protect it from any debris that gets into the tank. Holley offers a 3/8" barb screen in their kits that could probably be purchased separately.

The pump will be close to the tank but higher than the outlet of the sump (I'll probably mount on the rear frame rail behind the bumper). Thanks for the filter #, $17 works for me!