The turbo had one job, to force the fuel mix in the right direction into the cylinders. It was so hot that without the turbo the mix started backing out of the manifold due to expansion from heating.
The first engine was a v-twin made from the front two cylinders cut off from a Buick v6 block, with a Rochester 2 bbl carb. Later versions used a throttle body injector. There were also other types of engines, like in-line 4s later on, I think.