Should I swap to a new fuel tank?

[Erkenbrand]

I have a 1980 Mustang that was originally a turbo 4 car. I've been considering going to a Holley Sniper system on the 302 from an 83 GT that's currently in there. To do that I'll need both the feed and return lines, which my tank has. But the OEM Feed / Return aren't large enough to support the volume the Sniper needs.

I've been contemplating moving to a later tank so I can go to an intank pump.

Anything I should look out for? Can I use the original straps, etc?

Thanks for your help!

 

[broncojunkie]

I haven't done the swap, but I know people have used later tanks without major problems. I want to say there were actually 3 different tank sizes? My memory is crap these days. To go to the next larger tank size, I believe all you need are some longer bolts for the straps. The straps, technically aren't long enough, but the longer bolts will make up the difference. Part of the issue with modifying to the later/larger tanks is that in order to fit the extra capacity, the trunk floor was redesigned. With early fox mustangs, you will need to make some room. The quick and easy way is to massage it with a hammer. If you're careful and crafty, it probably wouldn't even be noticeable unless you point it out. Oh... and if memory serves me correctly (it doesn't), thecclearance issues are for fitting the 86-93 efi tanks in the early cars.

The mid 80's cfi setup also used an in-tank pump, along with a second external pump. I'm not sure if you would be able to use a pump in those tanks that provide the psi/rate you need. I do know that those pumps should be perfect for a carb setup. Just use the in-tank pump and not the additional inline external one with it. I'm going to try this on one of my project cars soon.

I'm not a fan of reusing the old fuel lines. If I'm replacing fuel lines, I just go ahead and design my own setup. My last one used a sumped tank, inline Holley pump, and braided line with AN fittings. Nice setup, except for the unbearably noisy pump. Sounds like a race car though lol!

In my job, I deal with a lot of pumps, pressures, flow rates, etc. I've come to the conclusion that pressure isn't dictated hy the pump. A pump may be a limiting factor, but restriction in the line is what creates pressure. A regulator will control pressure, but basically just by restricting the flow. I have seen the later efi pump assembly modified with a larger line. I figured they would have an upgraded pump these days that uses the stock hangar assembly but has larger lines. Do they? Anyway, if you can use one of these setups, in-tank is definitely the way to go. It's worth the headache.

 

[Erkenbrand]

I haven't done the swap, but I know people have used later tanks without major problems. I want to say there were actually 3 different tank sizes? My memory is crap these days. To go to the next larger tank size, I believe all you need are some longer bolts for the straps. The straps, technically aren't long enough, but the longer bolts will make up the difference. Part of the issue with modifying to the later/larger tanks is that in order to fit the extra capacity, the trunk floor was redesigned. With early fox mustangs, you will need to make some room. The quick and easy way is to massage it with a hammer. If you're careful and crafty, it probably wouldn't even be noticeable unless you point it out. Oh... and if memory serves me correctly (it doesn't), thecclearance issues are for fitting the 86-93 efi tanks in the early cars.

The mid 80's cfi setup also used an in-tank pump, along with a second external pump. I'm not sure if you would be able to use a pump in those tanks that provide the psi/rate you need. I do know that those pumps should be perfect for a carb setup. Just use the in-tank pump and not the additional inline external one with it. I'm going to try this on one of my project cars soon.

I'm not a fan of reusing the old fuel lines. If I'm replacing fuel lines, I just go ahead and design my own setup. My last one used a sumped tank, inline Holley pump, and braided line with AN fittings. Nice setup, except for the unbearably noisy pump. Sounds like a race car though lol!

In my job, I deal with a lot of pumps, pressures, flow rates, etc. I've come to the conclusion that pressure isn't dictated hy the pump. A pump may be a limiting factor, but restriction in the line is what creates pressure. A regulator will control pressure, but basically just by restricting the flow. I have seen the later efi pump assembly modified with a larger line. I figured they would have an upgraded pump these days that uses the stock hangar assembly but has larger lines. Do they? Anyway, if you can use one of these setups, in-tank is definitely the way to go. It's worth the headache.

Thanks, I appreciate the feedback. If I do it I'm going to go in tank, probably using Holley's in tank pump. Just get a big hole saw and give it an opening. Along with braided lines and AN fittings.

For now I'm sticking with what I have. I have to have the car road worthy to make Power Tour, so I have to stop adding to my list.

 

[Erkenbrand]

I've started heading down the path of an in-tank fuel pump. I'm going to use Holley's returnless pump, but I'm going to use it on the original tank for the 1980. With the Holley I can mount it in the top, incorporating the existing vent hole. The Holley has its own vent point. I'll keep the sending unit, and plug the fuel ports there.

From the measurements I've done I'm pretty sure the pump will clear, but I might still give the floor a tickle with my friendly 4lb persuader.

I'm doing all of this using a new tank and sending unit. Figure if I'm dropping the old one it's time to just swap. And I'm a lot less concerned about using a hole saw on a tank that's never had fuel in it.