I would pay up to 250 if it was dirty but good shape and I needed one. If a nice one walked up and I didn't, I'd buy for 175-200 to put on the shelf. Anything under that range you can flip quickly if you decide not to use.
Look closely at the second bolt back from every corner, if overtorqued they can crack.After that, standard FE manifold stuff, cranks near heater hose threads, cracks in valve cover bolt holes, cracks in thermostat bolt holes, stripped threads, creative repairs, etc. Mark down from there
I like a Street Dominator better, mostly for looks and strength of that 2nd bolt (all 4) but the SM is a good intake. It was put to pasture until Jay started dynoing LOL