is this a good turbo choice?

You asked your question in the right place, so I'll answer it the best I can...and try to educate you at the same time.

Theoretically YES....that particular turbo is close to the size your 360 would require.....maybe a tad on the "small" size though.

Diesel engines do not have the wide RPM band that a Gasoline Engine does....so where that Duramax would be tapped out at 4500rpm.....a 360 will rev into the stratospere in comparison.....6500-7000rpm +.....right?

6.6L is the size of the Duramax engines' bore x stroke....right?

V8 for V8 the 360 is .7 of a liter smaller.

Without a Turbocharger in place......which engine would require MORE AIR to run throughout its RPM band?......the 360 right?

With the addition of the turbocharger, sized by a GM Engineer for a 6.6L Duramax power levels......you might begin to see that this turbo would be one of the smallest that you could put on a Gasoline Blow Through V8 and not be restricted by the turbine side by 6000rpm.

Yes You could Use it.....But WHY?.....a BRAND NEW Properly sized turbocharger that can support 750hp can be had for a REASONABLE investment (around $750) at Precision Turbocharger.

You (just like the other guy asking a comparable question in here) need a PT6776R turbocharger.

Ohhhh yeah.....this gig is Super Expensive too.....(turbocharger + the rest of the system)