What size v6 are you dealing with?
not sure its out of a vt commodore
Does it have a duel bolt pateren for the bell housing?
Even if the tran swill bolt to the 308 the converter will be wrong and will have to be replaced. As for the insides of the trans, they are not as strong as a v8 700r4 trnas.
So I would have to say no it would not be a good idea to put a 308 infront of a v6 700r4 trans.