I'm playing with a 1984(?) F350 with the 460 V8. It's been sitting carb-less for a while and we went to put a carb on it the other day and there is evidently a part missing. The fuel lines (a feed and a return?) come up near the front left of the engine but there should be something between them and the carb, maybe some sort of pressure regulator? I don't know what I'm looking for or where to find one. Any help is much appreciated!

 

It's basically a tee with a orifice in it. The majority of the fuel goes straight through the tee to the carb. But a portion of the fuel goes through the orifice and returns back to the tank. When idling in hot traffic, this keeps the fuel moving faster so it doesn't get too hot and vapor lock.

If all your stuff is missing, I would use one of these filters with the return in it instead. That means the filter that screws into the carb is then optional. You could put a fitting into the carb instead of the filter if you wanted to, since you would be using the filter with the return below.

 

P.S. The return line system usually means you have electric pumps inside the tank or tanks. But they did also have a system with a mechanical pump, and the special mechanical pump for these had a return line on it.

 

Be careful on the filters with a return.
The return needs to go at the 12 o'clock and it may not have a orifice so to much fuel may return to the tank and not go to the carb.
Could close up the return a little to force fuel to the carb.
Dave ----

 

The description says it has a orifice. I would not worry about clocking it at 12 0'clock, if he puts it up near the carb the whole filter will be at a high point anyway.

 

Thanks guys! Yes, it has electric pump(s). I guess finding the original part ain't going to happen so that filter is a good find. Thanks again!

 

Back in the day it was found if the return port was not at 12 o'clock it would drain the filter and for some reason also starve the carb of fuel.
Maybe if it was at the 3 / 9 or lower the fuel would not push the air out of the filter and not fill the carb?
AMC used this back in the mid 70's on the straight 6 232 / 258 motors.
So any filter that has a return on it like that one I put at the 12 o'clock just to be safe.

How is the hot fuel bypass run is the return top or?
Dave ----

 

There is a screen inside that vapor separator and a small orifice for the return line
They had a few different orifice sizes depending on the color stripe
Blue .040
Red .060
White .090
Mainly used to control hot fuel and return vapor to the tank
We used to put steel needles in those Holleys to solve the sticking needle issue with the new at the time alky fuel

 

A lot of people are adding these filters and running a return line on vehicles that did not come with it originally. The fuel they sell now tends to vapor lock more frequently than it used to. and you also get in trouble in the spring and during the winter on sudden warm days, when you have the winter time fuel formulation in your tank. The winter fuel formulation vapor locks even worse.