i was wondering, what is the reason for the exhaust passage that goes through the intake on a 454 from one head to the other? would it hurt anything to block them off completely ? thanks,
Fran

Its to warm the carb if you have a temp activated choke. You prob have an electric choke and you can buy gaskets that have block off plates built in. But if your gonna go that far,why not replace the intake with a nice aftermarket part?

In addition to warming the mechanical choke it also warms the intake charge so the engine runs better when cold or if it is really cold outside. Cars with carbs needed all the help they could get to run good with the lean mixtures necessary to meet emission standards in the '70s and early '80s. You could easily do without it on a boat. Most boat engines are modified car engines so that is why that stuff is there. If you are trying to make maximum power, you should at least block those holes off. The cooler the intake charge, the better. Some intake gaskets come with optional block off plates. Youl have to pull the intake to install them.

Good luck, Doug

thanks, i swithched to electric chokes already and blocked the passages too as that was my guess but the intakes are pretty good high rise dual plane units from the factory.