47-55.1 Using original heater.

[47 Fasttoys]

From time to time a thread comes up about can you use original heater. Many think you cannot because of the higher pressure when using modern drive train. So I have been running the original heater in my truck for the last 7 years. I run a LS swapped '47 COE which also has a vintage air under dash AC unit. Because a couple of weeks ago I started to loose a little coolant I was thinking maybe the heater was leaking. I built a test gig to test the original core at higher pressure just to see. Here are the results. The core will hold 16 PSI for as long as needed, at least 24 hours, so this is not the issue. I have also included pictures of the motor I used for 12 volts. As far as will it last? my build currently has almost 200k miles on it so yes it will hold up. This is my 3rd time using an original heater with modern engine. Hope this helps others.
Rob