I was consistently getting high teens with the 440 in my '72 crew cab truck; 440, 4bbl, 727, 4:10, 33" tall tires. I was running open chamber heads with KB pistons to get exact quench distances. Its definitely possible to get a big block truck out of the single digits, even pulling a load.

Here is a compression ratio calculator I've used in the past to help see where dynamic ratios fall relative to static ratio and cam events.

https://www.rbracing-rsr.com/comprAdvHD.htm