pic- identify this item thats screwed into this turbine housing...

was on, and would be going on if we were to buy it

and rear mounts use UNDER sized turbos

sts kit on an ls1 = approx pt67
front mount on an ls1 - nothing smaller then pt76

the last guy that tried to rear mount a full pt88 on a stock ls1 managed a full SINGLE pound of boost @ 100mph (wot)