[cj428mach]

Do you know about this kind of tank? It has an internal regulator and not one hole anywhere on the car will need to be cut for this system. Uses one 3/8 fuel line. You might need to provide more venting. Holley Sniper VK040044 1964-1970 Mustang/Cougar Fuel Tank and EFI Module Combo with 22 Gallon Tank

I think the Aeromotive Stealth II is a better setup and all your lines come out in the stock location. I also like that if you need to service the pump, it still comes out the top. Thats what I put in my 64 and am Very happy with it.

 

[cj428mach]

I prefer the earlier style Aeromotive tank because I prefer to keep the fuel lines and brake lines out of the driveshaft tunnel. The tunnel is small and a 3.5" driveshaft will take up most of the room. Also the stock location fuel lines can interfere with the Watts link frame.

I reused the stock feed line as my return and just ziptied my new braided feed to the original feed line about every 4 inches. No holes to drill and plenty of room, I'm a big fan of the factory location on the tank for lines. On my 69 Mach I'm running a Spectra tank because it was the first to have everything in a stock location, the Spectra tank though has other issues to deal with so I went Aeromotive this time.

 

[cj428mach]

^^ I agree, there is literally no reason to put fuel lines in your trunk when you have aftermarket tanks that use the stock sender location. The only time this changes is if you are making more than 450HP...5/16" lines can supply up to 600HP worth of fuel so at 75% capacity is when you need to start thinking about upgrading...even then, its preferable to mod the sender unit for a larger line than run lines into your trunk....they are often just soldered or brazed into place on the sender "cap". As far as vents go...if you want a vent, you can always install one on a new tank without too much work. The only time the top-mount tanks become worth it is in high HP applications. I have also never been a fan of unnecessary bulkhead fittings in fuel systems(and you do need a bulkhead fitting so you dont risk chafing) since its just another place for a potential leak.

Aeromotive makes a tank with 6AN fittings out the bottom of the tank for early mustangs. It should feed all but the extreme builds, and makes plumbing a breeze.