I currently have a clear (glass?) fuel filter on my 70. Last night, we ran a car fire on a 66 Impala. It was a gorgeous show car that went from stunning to smoldering in about 15 minutes. After a little investigation, we determined that the clear fuel filter had cracked (probably because it was against the intake), so I’m not driving another tenth without changing mine out. I have a 351C with a Holley Street Avenger 650 cfm.
Questions
• I’ve read on other forums that I should have a 100 micron pre-pump and at least 40 post-pump. Are these filtrations about right? Do I really need the pre-pump one for regular driving?
• Does it matter if the post-pump is installed horizontally vs. vertically? next to the pump vs. next to the carb?
• Is a 6AN large enough for a 3/8" fuel line?
• When using threaded fittings, do I need to use fuel-resistant thread sealer?
• Do I need to consider ethanol additives in my gas or using 91 octane?
• Is there a minimum flow rating (or total filter surface area)?
10 micron seems like overkill on a carb. Same with dual filtration.
I don’t think fuel filter orientation is a concern though my experience is with fuel injected cars. I’m interested to hear others input.
-6 is 3/8” and should be plenty for your car.
Teflon tape is fuel resistant.
I can’t speak to EtOH additives.
Filter area probably isn’t a concern for a street focused car.
Interestingly, I’d never considered that this could even happen until I was talking with a AZ Cougar Club member at a show on Saturday. He told me to get that thing outta there ASAP. I was going to anyway, but after extinguishing that Impala only 48 hours later sealed the deal. I was literally nauseous.
Do it like Ford did. Metal filter screwed into the carburetor inlet. Use no see through elements ever. Keep a fire extinguisher in the car next to the driver seat. I’ve put out under hood fires several times under the hood of other people’s cars with the fire extinguisher in my cars.
Most of the fires I have been involved with started because of a power steering leak. So be careful how your PS hoses are routed and replace them if they are 50 years old.
What is your fuel system right now? Steel tubing, rubber connecting hoses glass filter? Factory type. The reason I ask is most rubber hose connections are questionabale at best. Especially the one from tubing to mech pump inlet. Engine rocks, hose gets stressed. Any hose connections that are not straight and have any kind of stress corners on them are a leak looking to happen.
Especially between the pump and carb since that’s a pressure area. Ford had a big recall in the mid 70s, because the little rubber hoses to the carb would crack, spray fuel and start the car on fire. Use a metal fuel filter whatever you buy. Glass/plastic are a fire waiting to happen. AND CARRY A FIRE EXTINGUISHER in your car. Headline; $45 extinguisher saves $45,000 classic.
After my eye-opener, I’m in the process of replacing all rubber hose/clamps in my fuel system. I’ve a got SS braided line from pump-to-carb with a DEI heat shield already. I’m thinking I’ll put a 90° 6AN fitting on the pump outlet and connect the 40u filter to it, then use the braided line to the carb. I’m still undecided about adding the filter from tank-to-pump.
And yes, in my line of work, extinguishers go without saying. I’m considering going from a standard ABC to this Element E50 (Element | E50 – Element Fire Extinguishers). $80, but 50 seconds and clean agent is worth it.
If possible use 45 deg elbow, smoother flow. Sounds like you’ve been fortunate to not have been burned, (pun unintended). The only real problem with a filter before the Mechanic pump is it’s lack of ability to suck thru it. But, if you put it below the tank, the fuel will flow into the filter by gravity. Electric pumps mounted back by the tank, always use a filter between the tank and pump for it’s protection.
but I would suggest a clean agent version like this 
