yes thinking about it aren't those filters for between pump and carb?
fuel pressure keeps vent closed.
vapour allows it to open, and vent the vapour back to tank, until fuel hits the valve and it closes again, to maintain pressure to the carb
1970s mopar thing...
thicker the better.... well in theory yes, but as i say, the volume of the HOLE(s) in the spacer impacts the flow and volume of the plenum.
Mine are 1/8 inch, my carbs don't get very hot, but mine is port on port induction, and that causes the inlet manifold to get very cold at mid to WOT.
1/4 or 1/2 would do it i'm pretty sure... you have put a none conductive barrier made of card gaskets and phenolic resin in the way of the heat flow, metal does not touch metal apart from 4 studs and nuts so conduction is reduced dramatically.
pump positioning is dependent on the style of pump, but most decent electric ones are very good at pumping and absolutely dire at sucking. can they lift the fuel from the tank to the pump height in order to PUMP it?... probably, but take recommendation from supplier of pump,
if they suck air they tend to overheat so keeping them FULL and the fuel moving all the time helps with pump life... hence usual solution is pump from tank through fuel rail to regulator and back via return the fuel just goes round and round the system is never dead headed. but pressure is maintained by the regulator where it matters
in theory an In tank electric pump is the proper way for FI, being submerged they stay cool, a carb pump is less powerful, so inline pumps survive longer in that kind of application and have done since the ticking SU types on BL cars of the 60s/ 70s, but i see no reason why a decent carter mechanical pump with the correct pushrod and gasket thickness can't do the whole job.
they "suck" and "blow" well and self regulate .
an electric pump needs to be on a key switched relay supply with a rollover shut off...
other option is a swirl tank on the front inner wing
this is a 3 connector tank with a bosch or or similar pump submerged in it
pipe from your mechanical pump to fill the tank via inlet 1
and return from swirl tank back to the rear of the car outlet 2
The exit from the pump to the input of the carb via a regulator, in line, with pressure set for carb,
the regulator should have a return line to the 3rd connection on the swirl tank, inlet 3, or again back to the main tank, and cap off inlet 3 up front, either will do.
you are however driving around with a litre of extra fuel in the front of the car, its not under pressure in the tank as there is a return line, but you are in essence just heating up a load of fuel because the submerged pump uses the surroundings as a heat sink.
Its a lot of hassle
try the spacer first.
and try the vented filter in the line to the carb not the line from the tank, if its a mopar one you would be using it as per original 1975 mopar,
the back pressure of fuel seen from the carb keeps the vent valve shut until there is vapour behind it when you stop. Pump pressure then vents the vapour and closes the retun valve when you start.
If its aftermarket, follow the instructions i don't know what the intended purpose for it was originally. a petrol fountain is not fun, wrap it in a plastic bag when you experiment to stop inadvertent spray all over.
id be doing this work outside
Dave
