I'm attempting to put together a 4.10 turbo II rear end for my 89 RX7. Currently I have an ISC 5.12 which I'm replacing with the turbo II (Engine swap requires 4.10 gearing). My friend shipped me the unit in the pictures. How do you tell from the outside that it's a turbo II?
It takes just over 4 revolutions of the input plate to rotate the axle 1 revolution. I guess that's a 4.10?
I also need turbo II axles and have located a set. The seller said that axles are S4 or S5 specific. How do I tell which version, of the rear end, I have?
I understand the two versions (older FC or newer FC) LSDs work differently. Since I'm putting in a Kaaz I was told the difference does not matter so it just comes down to axles.... right?

Thanks,
Bob