just be aware the 1000 is a very different chassis to a 1200. Transverse leaf spring front end with double wishbones. Can certainly be made to work - there was an extremely quick 1000 coupe sport sedan up here years ago that retained the factory front end with a few torana bits and rx7 brakes. But it may be easier to make a 1200 /120Y/Sunny work than the 1000.

the 0-1600cc class isn't as big as it used to be. But if that's what you want to build it for, the SR16 would be the go. Heaps of aftermarket support and knowledge. And the hottest SR16 had almost 200bhp from the factory!