Holley Sniper on a 351c

[BowdawG]

@BowDawg

[i plan on using the stock steel hardline as my low-pressure return line now and running the supplied high pressure rubber line to the sniper EFI.]

Unless u are really sure its a new one. Really do not reuse any of the old line. The flow going other way, the rust inside the line (much more than you think), flushed at low carb pressure on one direction will get back into the tank. Guaranteed!

[i tried to start my install over the weekend and instantly hit a roadblock with the return line.]

hahah yes, on the promo videos its all done in 2 hours

[Did you come up with a good way to mount the sniper efi return bung? looks like there is enough clearance to the trunk floor to mount it nearby the vent, but no idea how to get tools into the tank to tighten it...]

In my install, i've replaced the vent by a sending unit. On this point, I can tell you, while its a good idea that fits our tanks. If you don't have an old sending unit but have a welding machine. Use the old vent for ref. Cut a plate of metal that fits, drill a hole in it and bent a tube, and weld it to it. Thats all you need really.

I did the way I did, because I had no idea. And just like every first time, you learn from it.

[Also where have you hooked up the 12v switched power? ]

In this thread, I've detailed the tank vent part that I did and that electrical part too.

You will see more installs and variations of the install, different solutions/roads taken by the owners.

https://www.7173mustangs.com/thread-holley-sniper-efi-and-robbmc-surge-tank-351c-and-fmx?pid=305177#pid305177

Thanks Fabrice!

I might have missed it, but since your return line is going in the top vent location, how are you venting the tank now? 

And for the pink wire to the ignition green/red - is that green/red wire under the steering column/dash or in the engine bay? 

Your 90deg fuel line brackets look awesome! Might want to think about a cover like a piece of plastic in the wheel well for the odd chance something sharp gets kicked up off of the front tire you don't want it puncturing a 58 psi fuel hose.

 

[Fabrice]

Thanks Fabrice!

I might have missed it, but since your return line is going in the top vent location, how are you venting the tank now? 

And for the pink wire to the ignition green/red - is that green/red wire under the steering column/dash or in the engine bay? 

Your 90deg fuel line brackets look awesome! Might want to think about a cover like a piece of plastic in the wheel well for the odd chance something sharp gets kicked up off of the front tire you don't want it puncturing a 58 psi fuel hose.

Excellent point for the venting. I completely forgot while busy. Was bit overwhelming as a total install with lots of extra work, and got starter/ignition issues on top of that as well. I still need to lower the tank a bit again and mod the current setup (where the sending unit electrics were cut) and add something like this.

https://www.holley.com/products/ls_power/fuel_tanks/fuel_tank_accessories/parts/19-174

I will probably use a european equivalent.

So far, in garage conditions, looks like the cleaned up popup gas cap or the unit itself seams to do the work. I haven't noticed pressure diffs yet.

But will install one very soon. todo++

I added the splice you saw, right after the contact at column. Its been a while, so I might say something wrong here, but I think I remember there were 2 wires of the same colour there, one has a resistance and its not the one you want. If you follow from contact+read diagram, you can't miss it.

Yes a cover is on the todo too, just like the one I did for the pump, in standby. The plate in place has 2 extra holes ready and waiting for me to go get a thin alu plate, fold and bolt it on.

As I was busy on my 71 past weeks, I haven't got the time to go buy some. I'll prolly drive by next week, when i'll go get my heads back after a cleaning at the machine shop which is just 200 meters away from this metal supplier.

On the todo also, something I haven't done during install is to cut the blue positive wire for the pump and add a light+off/on switch.

If you work on other stuffs, its handy to be able to disconnect the pump as it primes every time you turn the key.

For my 71, I will go EFI too, but plan make own metal lines from pump (at frame/back wheel) to front fender.

It was painful to install that part and I think it would fit better our bodies. Less maintenance and safer too.

I might redo that part on the 73 in the future as well.

 

[tony-muscle]

Thanks Fabrice!

I might have missed it, but since your return line is going in the top vent location, how are you venting the tank now? 

And for the pink wire to the ignition green/red - is that green/red wire under the steering column/dash or in the engine bay? 

Your 90deg fuel line brackets look awesome! Might want to think about a cover like a piece of plastic in the wheel well for the odd chance something sharp gets kicked up off of the front tire you don't want it puncturing a 58 psi fuel hose.

Excellent point for the venting. I completely forgot while busy. Was bit overwhelming as a total install with lots of extra work, and got starter/ignition issues on top of that as well. I still need to lower the tank a bit again and mod the current setup (where the sending unit electrics were cut) and add something like this.

https://www.holley.com/products/ls_power/fuel_tanks/fuel_tank_accessories/parts/19-174

I will probably use a european equivalent.

So far, in garage conditions, looks like the cleaned up popup gas cap or the unit itself seams to do the work. I haven't noticed pressure diffs yet.

But will install one very soon. todo++

I added the splice you saw, right after the contact at column. Its been a while, so I might say something wrong here, but I think I remember there were 2 wires of the same colour there, one has a resistance and its not the one you want. If you follow from contact+read diagram, you can't miss it.

Yes a cover is on the todo too, just like the one I did for the pump, in standby. The plate in place has 2 extra holes ready and waiting for me to go get a thin alu plate, fold and bolt it on.

As I was busy on my 71 past weeks, I haven't got the time to go buy some. I'll prolly drive by next week, when i'll go get my heads back after a cleaning at the machine shop which is just 200 meters away from this metal supplier.

On the todo also, something I haven't done during install is to cut the blue positive wire for the pump and add a light+off/on switch.

If you work on other stuffs, its handy to be able to disconnect the pump as it primes every time you turn the key.

For my 71, I will go EFI too, but plan make own metal lines from pump (at frame/back wheel) to front fender.

It was painful to install that part and I think it would fit better our bodies. Less maintenance and safer too.

I might redo that part on the 73 in the future as well.

The venting will have to be through the cap so make sure the cap allows air in and out.

 

[Fabrice]

@tony,

Yes in garage looks like the orifice in the cap does the work, even with the huge temp diffs of the last weeks but I don't know if that would be enough in driving condition yet. Is it on yours?

 

[tony-muscle]

@tony,

Yes in garage looks like the orifice in the cap does the work, even with the huge temp diffs of the last weeks but I don't know if that would be enough in driving condition yet. Is it on yours?

So far it works. However, I got a screwdriver through the orifice to make sure it is open. I think there were designed to be one-way venting. Double check that air can go in and out through the orifice.

 

[Fabrice]

I'll recheck that this weekend.

I don't know if the other type of caps have this vent/membrane.

In case its not enough or if the cap isn't having the option. Installing the vent valve or similar as on previous link, is just a matter of adding a small extra nipple to the plate on top tank and place the valve somewhere above tank level.

 

[Fabrice]

Among other things, I've checked this weekend, it's breathing thru the fuel cap just fine. Even with this very hot weather where fuel probably expends a lot, no sign of irregular pressure. Same after it ran.

As the fender is almost done and will be bolted back on soon, I needed finish what I've postpone for ages: make a small shield to protects the filter and fittings.



Now its done, install complete!