Holley 700 DP on a potent 350(the one in my sig)

Runs a little rich at idle (checked the plugs) Makes great power from 2000-3800rpm, dies out after that. Punched it in first gear to 6000rpm and shut it off before it got to idle, burned off all the crap on the plugs.

Stock jets and PV. 67,76 6.5 I think. Fuel pressure always 8psi. Never backfires or sputters, so thats good. just lacking alot of top end power for a 234/242 cam.

I probably need to put in a smaller PV and bigger jets?

 

Idle richness=

Remove the carb, flip it over and look at the throttle blades in reference to the idle fuel transfer slots. readjust so that .030" of slot is exposed on both pri and sec.
replace the PV with a 3.5 or 4.5" (must remain closed at idle)
Reinstall the carb with the PCV valve hooked up properly.
with vacuum advance disconnected, start the car and let it warm up without touching the throttle speed. Increase the ignition timing at idle to 24 deg BTC. When the car is warm adjust the idle mixture screws to best idle quality and vacuum.
Should now idle rock steady at 700rpm.

Now you need to remove the distributor and modify the advance curve to allow 24 deg initial BTC @t idle and 34-36 at high rpm. (you need to restrict the mechanical advance travel)
Your engine's big long duration cam requires much more initial timing at idle (24-28deg) than a stock or mild cam does. Other wise the carbs throttle blades end up too far open at idle making the idle too rich with an off idle lean spot.

Now you want to adjust the vacuum advance to add another 15deg at high cruise.
24-28 initial 34-36 total at high rpm (3000+) with additional 15deg vacuum cruise advance = 51deg.

The high rpm leanout is likely caused by insuficiant fuel pump flow volume (not pressure) The fuel bowls are draining at WOT, starving the motor for fuel @ WOT.

Most stock and many hi perf distributors have 20-24deg of mechanical travel. Good for most stock and mild motors.
8 to 16 deg initialtiming)
You need more initial timing at idle (24+ deg)
You need to modify this for your motor because of its long duration camshaft, to about 10deg of mechanical travel to allow running more initial at idle while running 34-36 at high rpm (total timing)

 

when u say flow vs pressure, what do you mean? Does flow not create the pressure, or are you talking about a specific setup? If the pressure is always at 6psi, the flow can change while maintaining 6psi?

 

If you've checked the fuel pressure at the carb @ WOT and right to the red-line and it maintains 6PSI then you probabily have enough flow volume.
If the fuel pressure drops at high rpm in high gear the pump is not keeping up to the motors needs for fuel. (not enough volume) Sometimes this pressure drop does not occur to well into high gear on a WOT run.
Are you using a mechanical fuel pump?

 

was not thinking about WOT. Now that i think about it, your correct.

My self, i'm running a 192lph ford racing electric pump with a mallory regulator feeding an edl 1406 4bbl

 

Hook up a fuel pressure guage @ the carbs fuel inlet and go for a ride.
Watch the pressure guage at WOT thru the gears. if it drops lower than to say 4psi the pump isn't keeping up with the motors fuel demand thru your system.
The fuel pump's rated fuel flow (LPH) and the actual fuel flow volume from tank to carb thru all the various restrictions and turns are often two different things.
both edelbrock and holley sell differnt size fuel inlet needle and seat assembleys. more seat area allow more fuel flow into the carb per # of fuel pressure, but make fuel level control more critical. high output motors need larger than stock (out of the box) needle and seat size many times.
Edelbrock's Banjo style fuel fitting tends to be a bit restrictive.
This restriction to fuel flow will not show on the pressure guage. An Edelbrock carb can be modified to allow dual fuel inlets like a holley by drilling and tapping the fuel inlet boss on the other ( drivers) side of the carb and installing another fuel inlet fitting.

 

Timing has been 16* initial 36* total. The distributor has already been modded so theres no vacuum advance. Throttle blades are set.

I have an in tank electric pump. Wouldnt too small jets be a possible cause of it leaning out up top? It dosent lean out real bad(white plugs) just a little, and it realy stops making power.

 

I just took the car out, still no top end. I paid close attention to the speedometer this time, and the car stops accelerating past 4500rpm. Mabey my lil V6 clutch is just slipping? Cuz it still revs (but kidna slow I think) but never misses or pops like it would do if were starving for fuel. If the clutch is slipping, its not doing at like one point all of a sudden, it dosent immedietly rev like it just suddenly slipped. Ill be swaping trannys this month, I guess Ill have to wait and see

 

You could try 71 and 78 jetting but I think you have a fuel flow problem.
Althou your "in tank fuel pump" makes lot of pressure at idle. it may be starving the motor at high rpm in high gear.
Instll a fuel pressure guage at the carb and see if the fuel pressure is steady at WOT all the way throu the rpm band. May not drop until you're in high gear at WOT.

 

wouldnt I need a fuel pressure gauge inside the car?