Hi, unfortunately, the transmission is the only major part that was replaced. there is a M22 in it now, but when i bought the car, the seller told me that the transmission was replaced as a warranty replacement back in 1970, according to the people they bought it from.
The broadcast was not under the gas tank, i suspect the gas tank was replaced at one point as well, Daniel the person helping me with the restoration specifically went looking for the broadcast sheet when he removed the tank. He is pretty sure it is a replacement gas tank.
But all else looks right, the block has the double humps and correct casting, the intake manifold, carb is a DZ, exhaust manifolds, rear end, frame, dash board, etc
I bought this car from an attorney in San Francisco that repossessed it from a husband that didnt pay the bill for the divorce. After i purchased it and had it checked it out, the attorney let me talk to the wife and that is how i got the information i do have. The Attorney had the car checked out in San Francisco and had it confirmed that it was really a Z28. Honestly, i dont think it was all that reliable, you all are so knowledgeable and helpful.
I wish i knew more