You have I4, I6 and V8 FP and XP. When the other engine types have been developed and balanced calculation wise, you will get them. But that won't be for a while yet.
Everything will come at some point. There are videos on the Automation game channels (very early though) which show, that the calculations for V12 V16 etc. are pretty much done and working, but making assets and animations for every engine configuration and making that stuff line up, scale properly and not bug around like crazy is a pain in the arse from what I could tell.