Slant Six 225 (1975) Post Valve Lash

Looks and sounds like it's running really well! I'm not hearing any valve tick.

Stall at idle after coming off a higher speed is not caused by insufficient fuel pressure. Low fuel pressure causes the engine to stumble and sag under high-demand conditions (heavy load, high RPM) when it's gulping the fuel outta the carburetor faster than the fuel pump can refill it.