@Splangy
Harrisons came in chevys ... early heaters were clamshell style rounds
They show up on eBay and are very close in look to the denso... as well as Bosch and the Brit stufff like Clayton
That one is most likely 50’s
oh, I’ve got a clamshell. It’s going In my LV.
I only posted the Harrison to show another vintage aftermarket heater.