OK So I got my answer... NOT legal to remove or use an alternate overflow bottle in IT. Bummer I kinda wanted to run an aftermarket one as they are much less expensive and I could mount it near the firewall away from the front of the car.
Oh-well Stock it shall stay!!
Stephen
3. Engine Cooling System
a. Any radiator may be used, provided it is mounted in the original
location, maintains the same plane as the original core and
requires no body or structure modifications to install. No new
openings created by fitting an alternate radiator may be used
for the purpose of ducting air to the engine.
b. Oil cooler(s) may be added or substituted. Location within the
bodywork is unrestricted, provided that it/they are not mounted
within the driver/passenger compartment.
c. Cooling fans may be removed or replaced. Electrically operated
fans with manual or automatic actuation may be fitted.
d. Thermostats may be modified, removed, or replaced with
blanking sleeves or restrictors.
e. Air conditioning systems may be removed in whole or in part.
f. Screens of one-fourth (1/4) inch minimum mesh may be
mounted in front of the radiator and/or oil cooler(s) and
contained within the bodywork.
g. Engine coolant fluid, coolant/heater hoses and clamps may be
substituted. Heater hoses may be plugged or bypassed (looped)
or removed. Heater water control valve(s) may be added or
substituted. Heater core shall not be removed.