440 big cam (no cam info was in motor when i bought the car) Stock cast 4 hole intake. Pro's and cons of useing a carb spacer. None 1 or 2 inch?

There is no answer beyond trial and error. If you are running a AFB after-market carb, the manuals even tell you to use a 4 holer, which they LOVE! Since this is my preference for carbs, I have a pile of 1/4" 4 hole spacers that I stack up to find the best height for my particular engine (and no two have been the same). Once I have found the "sweet spot, I buy a phenolic spacer of that thickness and run that.

Everything I have read says 4 hole spacer for street use, even with a single plane intake. Raising the carb up off the intake has a slight tunnel ram effect that helps performance (at least in theory). But their main purpose (when constructed of wood or phenolic) is keeping heat away from the carb to avoid hard hot restarts. I have a 4 hole 1/2" phenolic on top my stock iron 340 intake and also a 4 hole 1/2" phenolic on top my LD340 on my 360. In my case (A bodies) that's all I can get without cutting the hood for more clearance.