Long crank on hot start is usually a fuel boiling or leaking issue. Make sure you have the thick insulator gasket under the carb. If your passenger exhaust manifold still has the EFE valve in it make sure it is not stuck closed or partially so causing excess intake manifold heat from the crossover. If it is a Holley carb it could be a leaking power valve. A more detailed description of the engine and fuel system would help.