I figured before to prevent tank gunk from ruining pump, but pump gunk, should it ever fail, could kill FI.

I'm not a FI guru, insert legal qualifiers here, my car is carb'd and I have filters on both sides. I hate dirt jets...

Is silly OEM square filter required, or can I use some other?

FI or carb???? if FI i'll differ, my quick answer would be there are after market filters out there. Carb no problem...

Carbs run on low pressure so the cheapo clear plastic ones will work.

FI runs on signifcantly higher pressure and if on the pump side needs one designed for FI. They are usually metal clad.

I have the clear-plastic FRAM one AFTER the pump. I have the pump up front, and the filter in the engine bay. Only because I didn't have room up front. I think I'm going to re-locate it up front when I re-config the lines. I'll need to pull the tank to do it though.

BTW: I'm running carbs, it'll be different with FI.

before pump. forget those little cone shaped, cheapo, type 1 style filters. jmho.

k

For FI, always before the pump. Although it's possible, I have never heard of a roller pump failing catastrophically enough to take out the rest of the fuel system. OTOH, inadequate filtration of tank gunk will kill a pump in a few thousand miles. FI roller pumps have very close tolerances and high flow, and their filters need to accommodate both. Use the stock filter (or something equivalent) for stock pumps, always.

As for pumps for carbs, I would check with the manufacturer.

Add one "horror story" which follows one of the previous posts. My '71 was sputtering and stopping without fuel flow so I figured the first cheap thing is the filter (yes the square one). I caused the smallest of constrictions in that crappy PVC line and "voila" killed the pump. Easy to do. Be careful since the silly square thing slips into a welded bracket which on mine was corroded. Long story short, replaced the fuel lines with decent ones (no possible fire hazard), rebuilt pump, recalibrated MPS, new distributor, new electronic point systems and with my hydraulic cam and valves, a much better running machine which needs much less adjustment.

Just be careful with that fuel filter. What seems like a $4.95 fix can turn into a major headache, especially since most of the parts are now obsolete and no longer available even at Pelican.