The concrete blocks I'm referring to are solid concrete wall stone/caps that are dense as hell, cinderblocks on the other hand can easy crumble. I stacked 4-5 of those under my Saturn and trust those more than any jackstand on the planet, it's so solid the car hasn't moved at all in months. Ask Dan, he's seen them, he'll agree.
The ones I used stacked under my car are wall caps made by techo-bloc, got them from my walkway (good thing I didn't glue them down yet lol). We sell them at my dads wholesale landscape supply company, they're high quality. If you drop one of those from a rooftop they might crack in half, unlike cinder blocks which would totally disintegrate.
IMO a wheel would crush easily under the sudden weight of a truck/suv, especially if it's just aluminum.
So yeah Gramps, DO NOT use cinder blocks, please.