All Decked Out

I have a 1964 383 4-barrel motor with the
518 Heads. I would like to know what the
CR would be with a zero deck height. The
motor is bone stock.

Usually, CR “guesstimate” questions
are dismissed out of hand by me, because
there’s a bunch of unknowns that simply
need to be measured, however, with zero
deck height and assuming flat-top slugs,
there are fewer variables, and those that
exist can be reasonably approximated, so
I’ll take a shot.
For the sake of this guesstimate, I’ll
assume standard bore and stroke (4-1/8˝ X
3-3/4˝), a 440 + 0.040˝ head gasket diameter
(4.370˝) gasket thickness of 0.030˝
compressed, and guess at 80cc for your
ancient (and very valuable) #518 Stage
III MW heads’ chamber volume. I will take
your zero deck height number (without
asking how you achieved this). With those
numbers I come up with 11.57:1 CR.