Hey All:

Since I am now a year wiser, I thought I would ask for some help in rectifying the ongoing fuel delivery saga on my 333 carbed Fox vert. Car put down 388 hp at DaSilva; but was running at 14:1 AFR; so it was lean with some more power available. Locked out distributor, 37* timing; marks on plug electrode indicate perfect timing.

Full AN8 feed, return and vent setup; sumped OEM tank; Pro Systems 780 road race carb; ported Victor Jr Intake Mallory billet return regulator; Comp 140 Mallory pump

Pump started getting noisy once warmed up; even after I relocated it parallel to the sump output lines. Idle and fuel pressure appear to be stable, however the throttle response and cleanliness of the idle varies. Makes no difference if tank is empty or full or anything in between.

Burned out a Holley billet HP150 last year during the heatwave - Holley blamed the ethanol content; been only running Shell 91 since. Replaced the Comp pump yesterday with known good Edelbrock and same thing continues to happen:

Car has killer throttle response and power like a raped ape when engine runs the first 10 minutes.
AFR looks good, a little rich, meaning I need slightly smaller primary jetting; but it's good to dump fuel on a locked out distributor to keep it from pinging/ detonating.

Once warmed up, AFR goes full lean and only shows acceptable numbers while decelerating with no throttle. At highway speeds it sometimes does not even do that unless down a hill. Throttle response and power disappear. Plugs look great other than a couple have the soot ring around the outside, due to the overly large primary jets. Once it does this, no top end power and for sure a lack of fuel. Yesterday she definitely ran out of fuel on a 3rd gear 6000 rpm on ramp honk; so is it not getting the fuel volume or is the fuel aerated or is there more air going into the motor?

About to delete the return setup and try running the pump with out a regulator and then with my old Paxton deadhead reg.

Could it be:
fuel is simply being aerated from being dumped at the top of the tank thru the return line (no tube; simple splash down).
a vacuum leak (between the intake and heads or ?)
the carb is doing something goofy? Float levels etc are fine

Water temps always between 170-180 even on scorching days, other than when stuck in traffic.


Any suggestions or comments most appreciated - the difference in power and drivability is huge and I'm running out of patience.


Thx boys and girls