My original motor needs a make over. I was going to fit a post 74 motor. Am I going to be able to do this without any permanent changes to my car? I will be refitting my original motor so as to keep all the numbers right. What do i need to look out for in the way of parts and tricks of the trade?

Besides some metal plates on the engine mounts there will be the issue of the alternator, regulator and ballast resistor needing to be on the other side of the car - so if you can be tricky and mount the alternator on the same side you can make it a temporary mod.