gt3071 turbine housing identification

What's the best way of identifying between the .64 and .86 housings when the turbo is still in the car? When I had the engine out I had a look for markings but there were none.

The .86 will be physically bigger but i have nothing to compare it to either way? Would i be able to measure the width of the housing as a crude indication?

Achieves full boost by around 4k rpm if that is any indication, my map is well off however.

Only picture I have is below.

Look for any sort of label on it because if it is larger it would have come from a third party turbo supplier.which is one way to tell.
Has it got the std 3 bolt flange on it as they are normally .64.

If there is no markings, I could be wrong but if it's a 4 bolt flange I think you could tell by measuring the gap between the studs. I remember I accidentally brought a .86 flange for my turbo and it wouldn't fit as the studs were smaller on the .64. I'll see if I can confirm

3 bolt on the compressor housing? No it's a beaded end for a coupler, are you thinking of a 2871?

Which flange woody?

Any part number ?
64AR tends to end with a 3
86AR tends to end with 20 or a 4

Nothing I could see but it may be on the block side of the turbo so it's hidden.

Better ways of telling but full boost by 4 would point me towards .64 but its no way to tell

I'll need to pull it off one day for a look then!