do not take your thermastat out
do you have aftermarket guages????
mount the fan directly on the rad, piss all that alu sheets off,
if you knew a fabricator, you would get them to make you a shroud that has the fan about 25mm off the rad, as there is a static deadset infront of most fans, so having it mounted 25mm or so off the rad, will allow the fan to work at its best