Pontiac didn't have what we would call big or small blocks.
They all had basically the same external dimensions since their introduction in 1955 as 287 and grew through out the years.
The 350 was derived from the 326 and the 400 from the 389 -differences were bore and stroke.
Here's info on the engines - Pontiac V8 engine - Wikipedia
They all had basically the same external dimensions since their introduction in 1955 as 287 and grew through out the years.
The 350 was derived from the 326 and the 400 from the 389 -differences were bore and stroke.
Here's info on the engines - Pontiac V8 engine - Wikipedia