Won’t start

So as I’ve posted a few times now I just swapped my stock intake and 2 barrel carb to an LD4B Edelbrock intake and a 600 cfm Holley carb that I rebuilt. Also changed from the stock fuel pump to a mechanical Holley fuel pump. Everything else on the 318 is stock. Went to try and start the car last night and it wouldn’t start. It would want too when I had my foot on the gas but wouldn’t. Also had one pretty barely backfire through the carb. I never pulled the distributor during the intake swap. I did take the cap off but there was only one way to reinstall it. Also I’ve checked the fuel line going up to the carb and it leaks when I start to loosen up the fuel line. I haven’t checked for spark yet waiting on an extra set of hands for that. I found a ground that was Almost completely broken off and I haven’t tried starting the car since fixing that. My gas gauge has been off and it’s reading low so I am going to fill up my gas can and put about 4 gallons in the tank see if that helps. The engine ran fine before all this. Only did the swap since I had the parts and had a bad thermostat and leaking 2 barrel. I haven’t spotted any leaks or any other frayed wires or vacuum lines not connected. Any ideas on something I’m missing? Could it still be a timing issue even tho I never removed the distributor? Thank you in advance for the help.