Re: 600 CFM Holley vs Edelbrock
You will not find a satisfactory answer to your Holley vs Edelbrock question. No doubt, Edelbrocks are cheaper but I prefer the Holley.
If you boat in freshwater only, the Edelbrock Performer intake will work well. It is a real no-no for salt water use unless you have a closed cooling system. Just do not use the Edelbrock RPM Performer intake, it has too high of an rpm range for marine motors.