New GN Owner - Please Help ID Turbo in My Car


New Member
Jan 8, 2008
Sorry for the long post.

Just took this turbo off the GN.

I'm trying to figure out what turbo it is as I will be buying a new turbo for the Grand National in the next few weeks, I need to have a starting point so that I know what the engine previously had in it before I begin to modify.

All the PO could tell me was that he upgraded the turbo and down pipe on the GN after he did in the head gasket. His then mechanic put this turbo on and never told him the specs on it. I figured it would be easy to figure out with the casting numbers and stuff. I'm pretty confident it's a T3/T4 Garrett but i'm not 100% sure what one Someone explained that it may just be a stock turbo, but I'm really not sure.

I'm just hoping someone can give me more specifics in regards to it.

Intake side it says A/R .60 M10

Exhaust side it says A/R .63 M3 and what looks like an 82 under it (could be a 62 but looks more like an 8).

Has an internal wastegate but I thought all these came w/ an external.

Also, I'm looking for a recommendation for a new turbo for the GN, it's has a 3000rpm stall, Upgraded injectors, (I believe they are 49 lbs now). I will be upgrading the intercooler to a front mount as well it has a turbotweaks chip in it. (I'll buy another chip based on which turbo is chosen for the car).

My goals are to keep it streetable, but to have some kick, Basically a turbo upgrade with a chip and upgraded intercooler that would make it a decent 1/4 mile car and a decent DD.

Any recomendations will be very helpful and appreciated!