Otter chassis question

[Grant Bowker]

Sence you are doing a cosmetic recreation, you have greater liberty while staying close to the spirit of the original.
Although much harder to find the chassis for a C15TA or another armoured version (either Fox or Otter) might be your best starting point as they are already set up for the 270 engine that the original used to allow for the greater weight (and the chassis will be re-inforced for the weight).
If original chassis are not available, you could use the chassis from the Gun tractor (also reinforced but they originally 20" wheels instead of the 16" used on the Otter). The gun tractor also had a 2 speed transfer case rather than the Otter's one speed. This is an advantage for slow parade work, but less originl, your choice.
On the other hand, the C15A had 16" wheels, single speed transfer case, correct wheelbase, no winch and is relatively plentiful. All positives for recreating an Otter replica for your project. To add power without having to modify the C15A frame to fit a different engine you have the option of a later 235 or 261 that would match or exceed the HP of the 270 (and probably be better on torque too).