Fuel system issues

[Rocket350olds]

86 cutlass supreme with olds 355 rocket im running a edelbrock avs2 1906 650cfm electric choke with spread bore to square bore aluminum spacer and I started having issues with fuel draining back to the tank didnt have any issues with that for the first year of having the carb on and since then its extremely hard to get started after sitting for a few days or after I fill the fuel tank and when I shut the engine off for 5 min and go to restart I have to hold the accelerator pedal to the floor to get restarted.
Should I switch to a holley setup not sure if it would be easier to tune

 

[ELCAM]

Running an electric or mechanical fuel pump?

Sounds like the float is out of adjustment or the needle is damaged or blocked with debris. If the charcoal cannister is full of fuel you will have to address that too after you solve the float issue.

Edit:

Was downloading something earlier so the Pic you posted was taking to long to load and not working.

I see the mechanical fuel pump so I revise the question. Running an electric fuel pump with the mechanical?

I don't see a fuel filter though it could be under the air cleaner. Does it have a fuel filter?

 

[64nailhead]

Switching to a Holley is not going to resolve your issues.

 

[Rocket350olds]

Yes mechanical fuel pump and fuel filter under the air cleaner

 

[g0thiac]

86 cutlass supreme with olds 355 rocket im running a edelbrock avs2 1906 650cfm electric choke with spread bore to square bore aluminum spacer and I started having issues with fuel draining back to the tank didnt have any issues with that for the first year of having the carb on and since then its extremely hard to get started after sitting for a few days or after I fill the fuel tank and when I shut the engine off for 5 min and go to restart I have to hold the accelerator pedal to the floor to get restarted.
Should I switch to a holley setup not sure if it would be easier to tune

I would try seeing first if it is a fuel issue or not.

It could be a fuel filter, a pump, or maybe even something different like a wild vacuum leak.

 

[Rocket350olds]

When the fuel drains back to the tank i have to pressurize the fuel tank to get fuel back up to the carb

 

[ELCAM]

Look for leaks in the fuel line between tank and pump especially the rubber on the tank and fuel pump end.

Thinking about it more The leak in the fuel line is likely in the rubber hose between the steel fuel line and the fuel pump, Likely the pressure from using compressed air to push the fuel up to the fuel pump increased the fuel pressure enough to bend the float.

 

[L92 OLDS]

What happened to the Q jet that came on the engine? I would toss that Edelbrock in the trash. I’ve never had a good experience with Edelbrock carburetors.

 

[Rocket350olds]

I dont believe the float would be bent because I have to blow air from the carb inlet hose back to pressurize the tank and it will flow up to the carb and the q-jet was in poor condition and probably not big enough cfm

 

[ck80]

When the fuel drains back to the tank i have to pressurize the fuel tank to get fuel back up to the carb

You should never, ever, ever have to pressurize the tank to get fuel to the carb. Ever.

Even on a completely dry fuel system, new tank, new hoses, new mechanical pump, all you would ever need to do is keep cranking the car and pumping the pedal some before it starts.