50 merc heater bypass

[50MercMetalHead]

Getting my merc back together for some fall cruising before winter hits. Im bypassing the heater cores and I’m wondering if I can just plug the fittings on the head and water pump or if I have to have a hose running between the two? Looks like I can just plug them, but I want to make sure.

 

[FortyNiner]

Plug 'em and get crusing before the snow flies.

 

[19Fordy]

I use antiseize compound on the threads. Use brass plugs. Don't over tighten.

 

[50MercMetalHead]

Thanks guys, I appreciate it.

 

[rotorwrench]

My 51 has a small brass valve mounted in the head to stop the flow for summer use. It may be an aftermarket part though and all it does is stop the flow. Plug it if there is no way the heater core will hold coolant.

The system on the 50 and 51 cars has a flow control valve that is controlled by the dash control lever but they can deteriorate and need either rebuild or replacement.