Here's a pic of him finishing adjusting the valves. It is close. He has to unbolt the shock and lower it a little to make sure the valve cover doesnt scratch.
Troy's car is a recreation of how a Hemi Super Stock car was delivered from the Hurst. The cars weren't that pretty. He was not trying to build a street rod Dart or Barracuda that has a Hemi.
Hemi motor with headers took about 10 minutes to put in. About 1/2 hour more to bolt the suspension up. Just drop body on drivetrain. No valve covers though. You need that clearance.