Here is the build in my coronet
383 .040 over
'66 closed chamber heads with oversized valves and mild port job
a touch over 10:1 compression
Mopar 284/484 cam
edelbrock performer RPM intake
full length headers
3" exhaust
750 afb
b&m shift kit
That should get you close to your 450 mark. I've ridden in built 440's that give a stronger initial head jerk during launch, but once it gets up in the revs, there is no stopping the 383.
The car originally had 3.23 gears. I put in a set of 3.91s. Good god did that make a difference.
I am debating on adding a set of 1.6 or 1.7 roller rockers and a single plane M1... not sure if it is worth the effort and $ though. It's a really easy drive now and has some good scoot for a big car.