Grubby,
My car is a 289 rather than 427, but these shots with the radiator out may give you some ideas.
http://www.clubcobra.com/photopost/s...hp/photo/67513
http://www.clubcobra.com/photopost/s.../size/big/cat/
The Canton thermostat upper, middle and lower housings can be rotated relative to each other. You can get the outlets at 90, 180. or 270 to each other.
Canton doesn't know it ( at least their tech didn't ) that you can rotate the segments. So, I took mine apart and got the outlets on opposite side of the stat's body. All the segments seal with 0-rings, just don't damage them if you take it apart.
Have read that a goal of a hydraulic installation is to have as few angled fittings as possible. Every time the fluid has to change direction, it increases resistance to flow and drops pressure.
Consider whether having the outlets on opposite sides may make the line runs simpler and avoid angled fittings as much as possible.
Also, it was worth the trouble to remove the radiator on my car. Measure and photograph where tight clearances may make problems as you mock up an installation. I made a cardboard box same size as the thermostat, and screwed the Earls fittings into the holes and was able to visualize what would work. Got the hose legths ~ right the first time. Well, they fit.
There are a LOT of posts on Canton, or other brand, installations on ERA 427"'s, so look around before you start cutting hose.
I have a lot of photos of the thermostat disassembled, and more of the installation. e-mail me I can send them out. Oh, auger bits are great for cutting holes in the aluminum bulkheads.
Fun project, and it does help to warm the engine up and then stabilize the temp.
Hope this helps a little!
Pete
http://www.clubcobra.com/photopost/s...hp/photo/67513