[SFfiredog]

I've been a Ford guy for ever and I've never heard of a double overhead cam 429. Ford did build 10 429 double cam engines in 1967 for use in the Can Am series. The engine was called the "calliope" and used the bore spacing of a 385 series engine
The unique feature was the double cams in the block, one operated the twin intake valves and one operated the single exhaust valve. Three valves per cylinder in a hemi style combustion chamber, very cool.
The engine was a full race effort utilizing a dry sump oiling system
and having the fuel injection throttle bodies cast directly into the head.
Here is a photo from the Monterey Historics
--Mike