Difference between 911/93 & 911/83 engine

[993C4]

What are the main differences between 911/83 & 911/93 engines? If my ustanding is correct, 911/83 are RS engines?

Is it possible to to convert a 911/93 engine to an RS spec'd engine and if so, what are needs to be done for the conversion?

And lastly, how reliable is an RS engine (as compared to 911/93 engine)

Thanks for your help

[Flat Six, inc.]

The main differences are the pistons, cams and the heads on the 911/83 have a threaded hole for the MFI fuel injector.

Otherwise.......the valves are the same size and intake port on the RS engine is only 1 mm larger. They are both 8.5:1 and 2.7L

RS engines run much stronger than the CIS 2.7 and yet are perfectly reliable......all things considered.

I hope this helps.