Well, I have a 202 Blue fully recoed out of a 1/80 WB ready to go into my 5/79 HZ and to be honest, the only real difference between the red and blue is the top end.

I've even quietly considered restamping the blue and painting it because i can't get any answers from Qld transport.

I cant really see the issue with using a blue motor; its no more powerful, has better airflow (12 port head v 9 port) and is more fuel efficient (which, when last i checked was a good thing) but according to the transport depot "oh no, you cant have it, its a different colour so it must be a totally different motor"