YES, the 6t75 fits! if it fits in a damn fiero with a LS2 v8 mounted with it it will fit in a wbody........

Good in here more people that cant figure out google and just say NOPE WONT fit.

Yes it will fit. So does the 6 speed from the G6. People have done the F40 swap before on a wbody also......

Controlling it. people said the 4t80 wouldn't work hmmmmm but it does.....

People said a ls4 and a 4t80 wouldn't work together but hmmmmm it does....

The OP wasn't asking if it was "bolt in"

LOL threads like this make me hate this site buncha nope motherfvckers that cant use google.

To the OP want to see some weird ass swaps google a little into the fiero world them fiero owners are crazy.

Ive seen every thing imaginable in a damn fiero like a ls7 mounted to a dog box NSX transmission.........

BTW as for transmission swaps unless your hell bent on using a 6 speed id go 4t80.
A they are cheaper and easier to find.
B they have already been put in a wbody with both v6 and v8 engines.
C the 4t80 is slowly but surely making progress in the modification/reliability category to hold pretty good power. I know of at least 2 people that have thrashed them with at least 700hp getting thrown at them.
D the tuning options are already worked out and sorted with multiple options........