I need to know if I can use any masonry circular saw with the appropriate blade to slot concrete wall.?

I'm looking to open a channel through a concrete wall, so I can run conduit or polyduct for an electrical installation. The saws specified for masonry seem a little small for 7 1/4" max diameter. I'm looking to buy a 4 or 4.5" blade diameter, but I really need to know if these will do the trick.