'64 GTO & 421 Engine

Can someone please clarify this for me...??
Was the 421 engine a "dealer installed option" for the first and best year of the "goat"????

The 421 engine was not a dealer option to my knoledge. They (Pontiac) campaigned one GTO with that engine combo at a shootout for a magazine but kept it quiet. There may be a possible car that the dealer did install that motor but the proof would have to be in documented paperwork.

there is one sitting in the basement of pontiac they built one and only one to find out if the 421 was a better power plant ive read alot about this mystery car..Go back to the pontiac factory they have a exhibite of all there old cars from the GM factory's all in factory cond,, Ive seen photos but as a option for the gto no there was only a 389,or a 400 then a 455 ,,and latter a 350..
The pontiac guy



travis williams

thanks joe. that's what i thought but i wanted to make certain. some people replaced the 389 with the 421 and they're trying to say that even though they did the swap, it was a dealer option.
i appreciate your input.