It seems that no one is able to answer this kind of question so I figure I'd ask it here:

The Hotside from the turboII I have has some pretty nasty cracks in the inside of the housing. I would like to replace that housing with a brand spanking new housing from an aftermarket turbo place (such as atpturbo.com) but i'm not sure of the classification of the turbo, or which turbo will work with it. I was told by certain persons that it's a T3/T4 Hybrid, but i'm not sure how much I trust that information.

What other turbo components will work with the stock turbo from an 86-91 Turbo?
Compression housings?
Turbine Housings?
Intermediate adapters (for oil and water)?
Any other modifications that could be done to the stock turbo.

(extra information: the compression housing i have on here now is a Garrett with the part number:409080-5009. I'll do some more research regarding that part number and see what turbos it fits--maybe that will point me in the right direction for the turbine housing?)

 

Based upon measurements of the turbo inducer and exducer (on the hotside, warning it is not extremely accurate!) here are a list of possible compatible turbos to try out--this is according to the information provided here.

For the inducer I measured a little less than 2.9375 in (dia). This means that the hotside can likely support:
T04R
GT40
T78 (unsure)
T88 (unsure)

Anyone confirm or deny?