I don't have all the specifics yet, but so far I know it is .30 over with aluminum heads, Mallory ignition, new innards, and less than 500 miles on it.
As usual, I am going to go out on a limb and cast aspersions about this prospect. It's HIGHLY doubtful that someone put Aluminum heads on a 326. So what you are potentially buying is just a 326 ... nothing more.
If that's the case, take a pass and find a 455 or a 400 to spend your effort on instead. You'll need to get everything from the drive shaft forward from a Firebird in any case, so regarding the time involved, having a motor on-hand isn't really saving anything.
Now ... if it actually HAS aluminum heads, please take the time to find out exactly what it is, whether 326, 350, 400, 428 or 455. All Pontiac V-8s look the same from the outside. If for some odd reason someone actually E-Headed a 326, buy the motor and take the heads off and use them on a 400 or a 455.
About the only realistic reason to have a 326 would be if it is the original motor for the car.
