Engine cuts out after driving 20 min, ideas?

[Osker]

OK friends, ….71 C10 big block, not a daily driver but I want to get it there.
Issue: Driving back from work, it is about a 20 minute drive, it was running fine on the interstate got up to about 75mph right before I got off, driving through town at 25mph after about two miles of that she shut down, just died while rolling. Sounded and felt like she ran out of gas, but I had ¾ of a tank. I pulled her off to the side of the street. I started her up and it runs for about 10 seconds at a normal idle, nothing missing or lumpy then she dies again, I did that 3 times but every time she would die out.

Outside temperature was 75, engine temp was normal, oil pressure was normal, battery is charged. She cranks fine every time.

A few weeks ago, the same thing almost happened on the interstate, but she kept running after the stumble and a slow down and I made it through town with no more problems and back to the house. I had driven her since then mainly around town and no stumbling or cutting out. Then yesterday she went flatline on me.

I’ll check it out tomorrow after work when I have some time. I’m thinking fuel pump or the in line fuel filter in the carb inlet? I’m hoping after sitting for a day she will start and run home where I can really dig into the issue.
Any recommendations I am all ears!

History:
Fuel pump (40 gph) replaced in OCT 2020 with a NAPA MF001 because old one was leaking from the housing.

After I replaced the fuel pump the Rochester M4MC started flooding out and she wouldn’t run. Taking the carb off I found that the well plugs had been epoxied, but the epoxy had come off and was left on the gasket after the carb was lifted off. I think the new fuel pump was flooding the carb out. Looking in the manifold there was a big pool of fuel just sitting in there. I changed the oil not knowing how much went down. Plugs were fouled and smelled like gas. I put in new plugs and wires. Instead of rebuilding the carb I purchased a rebuilt one from the Carburetor Exchange in El Monte CA. With minor adjustment to the fast idle she ran great, but I still need to raise it a bit as she doesn’t always start right away. I’ve been cheating with starting fluid. One shot of that and she hits right away.

Spec’s
Non-original 396 cu in engine block code 3916323
TH400
MSD ignition, Mallory, new cap in OCT 2020
New plugs and wires in OCT 2020
Spark Plugs = AC Delco R45XLS @ .035 gap
Stock intake

Thanks in advance. I’ll keep you posted with what happens or doesn’t.