Wouldn't start. Now starts!!???

[Dnrice]

Just brought my 71 C10 home from mechanic. First time home!!! Kids and wife love the look. It has 350 with a 350 turbo transmission and double hump heads. They changed the Holley carburetor which now has a choke and I drove it on the freeway fast, but not too fast because of the turbo transmission. It would backfire sometimes! Got home parked it and then tried to start it and it wouldn't start. It didn't turn. It was like it had a dead battery. Waited 20 minutes and it fired right up. What do you think the problem is? By the way, I am using high octane gasoline.