68 383 with 750 carb. Runs rich

That fuel supply line is a recipe for disaster.
First is the multiple gear clamps, that do not provide proper 360 degree clamping,
Second is the glass multi-piece filter,
Third is the soft lines.
How many failure points are there? I count 6 in that picture, including the glass filter sitting on top of the heat crossover passage. You only need one to burn your car down.
The boiling point of the lightest components of gasoline is ~95*F. In all likelyhood your carb will run hotter than that. Your fuelpump may be hotter than that. The fuel in your rubber line may be hotter than that. If just one of those 5 possible failure points, fails, the fuel may not even come out as a visible liquid. And as a vapor, it only needs a tiny spark to flash.

Oh, and just because the factory put the coil there, does that mean it's the best place for it?
Smelling gas fumes, with the engine running, is NOT normal,and probably dangerous.
I don't see an operational PCV system.
At some point, you're gonna want to hook up the vacuum advance, to that currently capped sparkport, but right now it has nothing to do with your hard hot-start.
Is that a 6-cylinder throttle cable? It looks a little long and is operating at a pretty severe angle where it exits the firewall; One would hope it never sticks at WOT
I'm not picking on you or your combo; I just care enough about somebody's hard work and time, getting it to where it is today, and enough about you to not see your dream possibly destroyed , possibly with you and a loved one(s) still in it.