Did I hear Heater and V8 conversion in the same sentence??
Heaters... the bane of my existence.....
I searched hi and low for a compact unit and ended up using the Smiths Beehive type.. nothing else looks better that that
I modified the water inlets and used elbows instead allowing me to plumb thru the firewall in the most discreet place. I also added a heater tap to regulate the flow of water and therefore heat.
The heater sits in a slightly different place to normal because of the modified firewall but more or less the same.. I'm not restoring this car so not overly concerned.
Im using fibreglass reproduction demister vents (by yours truly) and pool hosing to direct the air onto the screen.
For a rear demist, I got these little heated bars under a chrome cover that sucker cap onto the window. very discreet may come in handy one day.
Cheers
Ed