"915" Cylinder Heads on a 383
The 1968 and 1969 '383' had Flat Top Pistons with 10.0-1 Compression
with the top of the piston set 'above deck' @ .021".
And a 'factory' 'Shim-Type Head Gasket {.020"}
Despite that, it didn't stop many guys from attempting to pop on the
#915 Closed Chamber Cylinder Heads {swapping off the #906 Open-Chamber Heads}.
Sometimes it worked, and sometimes it didn't. It all depended on how the 383
Block {Piston Height} left the factory.
On a 'stock' swap out, if it worked, you gained about 1.1 in Compression.
If it didn't, the Piston had a 'party' with the Cylinder Head, and you usually
smashed the Top Land of the Piston, and ruined the Top Ring and smashed the ring-land slot.
