Do's it crank normal or slower on hot starts?
If slower, try less timing.
If same check carb float level and throttle plate/idle needle screw settings.
Try one thing at a time. If no change, reset that componate and try next one.
Could be 1, 2, or 3 things.

FWIW, i use a 550 cca battery mounted in trunk.
High torque mini starter.
Cranks 24-7 no prob. Sometimes alot with the dam female holley carb w/o choke...