My stock 34 v8 isn’t performing

[Rsb43]

Stock 34 model 40-
New gas tank, fuel line, carb, fuel pump distributor, coils all replaced with professionally rebuilt units. Entire wiring harness replaced. Original fuel “pick up” (inside the tank) not replaced as I was unable to obtain original style replacement and advised to reuse.
Issue- when demand for full throttle, engine is unresponsive. It will also pop through carb irregularly. If I am climbing a hill, I’m forced to downshift prematurely to ensure I’ll make the hill.
Any thoughts/suggestions appreciated in advance.....you all have been very helpful to someone whose recently entered the Ford world.....

[drolston]

Run a compression check. You may well have a sticking or poorly seated intake valve, which will cause it to pop back through the carb. If you find a cylinder that is significantly lower than the others, try drizzling a pint of MMO into the intake while jazzing the throttle. That will usually clear up the sticking. Kerosene also works.

[Karl]

Pick up/ Fuel gauges come up regularly on the swapmeet site here .
I coiud even send you one but the postage from New Zealand would make it uneconomic for you --Karl

[koates]

I see you are running around buying new parts for your ORIGINAL 1934 Ford. Whilst this might seem to be the way to go it is not really. Many newly manufactured parts today are not up to original specifications. Replacing parts is not the correct way to fix your engine problems. Learning how the different systems work and how to faultfind is the way automotive mechanics do it. Is your engine an original 1934 21 stud type.? What exact new parts have you fitted? As others have mentioned that a cylinder compression test would be a start. Also buy a vacuum test gauge and connect into the intake manifold and note the readings shown in the gauge chart. Has your distributor been set up correctly. Original type coil mounted on top of the distributor ? What brand of new carb have you fitted, they are not all good. Please list in more detail exactly what parts you have purchased. Regards, Kevin.

[koates]

Oh I forgot to mention the ignition condenser. What do you have fitted there. Most automotive shops these days are not able to test condensers properly. Not all new ones are good quality or have the correct capacity for the early ford V8. .36 microfarads was the original specification. Most modern condensers are around .23 mfd. Regards, Kevin.

[Rsb43]

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Sorry folks, I was remiss in mentioning the following: This is an original 21 stud v8. Compression test showed all cylinders within acceptable range. Also, carb, fuel pump, distributor, coils were replaced with rebuilt original ford parts. Everything was sent to a respected company rather than myself rebuilding it. The wiring harness was the only item that is “new”....

[Frank Miller]

I have seen spark plugs fail without reason or warning. This sounds like a spark issue of sorts. Higher cylinder loads will blow out a weak spark.

[drolston]

Good news that the compression checked out good, so a sticking valve is probably not the cause of popping back through the carb.

Another possibility is cross firing. Under load the coil needs to reach a higher voltage to jump the spark plug gap. If you have spark plug gaps too wide and/or deteriorated ignition wires, you can get some cross firing between ignition cables. Gap the plugs. Check electrical continuity from inside the distributor all the way to the center electrode on the plugs. Be sure all spark plug wires are fully and tightly seated in the distributor cap and tight on the plugs. Look for any signs of cross firing inside the distributor cap, like carbon trails.

[Phil Gillespie]

Air Cleaner filter? Could be the cause. Try a short run without air filter fitted?
Phil NZ