Gunner,
The MOCAL unit IS available with a 180 temp or, 212/215 setting (for a higher price I think). The CANTON only comes with the 215 capsule I think.
A big-block FE may be OK with a 180 temp, especially if the coolng system would have trouble staying ahead of the heating in traffic.
My small block 289/347, even at 10.7 comp just doesn't generate much heat. With a
oil cooler/AVIAD
oil pan if the thermostat opened at 180 I wouldn't gain much at all. At 215/220 the cooling system is overkill for the application, so no problem staying ahead of the heat.
The MOCAL unit is very compact compared to the CANTON. If the hose inlet/outlet orientation will work it may be perfect. Saw a 911 Porsche with MOCAL in the rear wheel well. Real tight fit. Seemingly no room for the CANTON to fit there.
Cobra's tend to have some some room up front so the CANTON may be a good choice, especially if you rotate the main housing segments to your advantage, ie: shorter hose runs without too many 90 and 180 fittings.
Pete