I have a Mallory 140 I have decided to hook up. I have both the 4309 (return line) and 4307 (dead head regulators). My feed line is -10.

Any recommendations?

If I use the 4309 return regulator I can only reasonably run -6 line as the return line due to hose routing room. Does anyone have experience where this has worked while feeding with a larger -10 line

or should I call it a day and use the dead head regulator?

This car sees a Lot of street miles, stop and go traffic as well.

In general, it is better to use a return style regulator for several reasons including longer pump life.

However, if you can't use a -8 AN or 1/2" return line with the 140 pump, go with the dead-head regulator as the -6AN return line is too small unless it is very short (say less than 4 feet).

RobbMc
Mallory Engineering Dept.

Thanks for the help Robb. So it seems the bypass regulators are really not setup or designed to "dead head" at all. So If you cannot bypass enough fuel they do not work. Whereas a dead-head regulator like the 4207 is made to do just that...dead head.

I will run some choices by you.

(1) Mallory Comp 250 with a dead head regulator using the pump bypass with a -6 line.

OR

(2) Mallory 140 and dead head regulator(s)

What kind of life expectancy should I expect out of the 140 dead headed ?

(3) I was thinking of running a New Carter 172 mechanical pulling through the 4207 regulator and the 140 for street driving and too and from the track. When at the track, turn on the 140 to push the fuel to the regulator and eventually to the Carter and on to the bowls. Regulate the fuel pressure to the Carter to 4 or 5 psi to limit the stress to the pump.

If the next time I race wasn't for points I would just replace the Carter and test it out. I can't afford to have a problem like last week my first day racing for points for the season in 10 days. I like to limit my setbacks to driver error, not mechanical issues.

They will have about the same life expectancy and brush replacement kits are available. The 140 is "internaly bypassed" with no need for a return, and the 250 is "externaly bypassed" which requires a return (or burn it up).

A short run of -6 return from the pump bypass to the tank may get the job done. You'll know right away if it won't because you wont be able to get the pressure down to 7lbs. If you get it down to 7lbs, your good to go!

My Mallory 250 with -8 bypass (pump to cell) stay's rock steady at 7.5 lbs and I can adjust it from 3 lbs to 15lbs with my Holley big port (dead head) regulator, I highly recomend this regulator it is diaphram controled and flows more than any Mallory regulator and at less cost to boot.


My Chevelle Page (http://home.swbell.net/kenladd/Home.html)

3830 lbs
All Steel with full interior
10.25 1/4 mile @ 130 MPH

tom, was it low on pressure when you used just the carter?

Brian,

About Mid track the pressure went to zero and the car nose dived, when the pump caught up it picked up again.

Installed a New Carter 172 yesterday and took a 70 mile cruise, pressure fluctuations just like the first one at WOT for 4 or 5 seconds, but no loss of power. My guess is the check valves may have begun leaking just a little or maybe the diaphraghm was just a little weaker than new. THis says to me I was probably on the "edge" with it anyway and a little loss of pump performance was enough.

Update Mallory 140 and 4207 dead-head regulator is installed. Just need to install a filter between the tank and the pump...Need one fitting which I will get on Monday.

I will run this pump for at least 4 weeks and touch nothing else on the car to see what performance difference if any.

you could probably be fine with just the 140, depending on how much pressure you run.

How much pressure do you run to the carb?

that is strange that the mechanical would die half track then pick back up. Have you spoken to anyone about what might be the cause of that?

7 1/2 to 8 to the carb will be the goal.

The only explanantion I can think of is the pump starting pushing/compressing air as the bowls and fuel log got low on fuel and then after about 2 seconds pressure shot up and I had power again. We'll see what happens a week from Wed.

I need a couple more fittings to finish the job. I will get them tomorrrow