Yep. They became junk, for a while. Obsolete for racing, no good for the street. Expensive boat anchors and not really suitable even for that purpose.
One of the things that occurred to me as I put my Spyder together is that the Raby Type 1 1915 I scored from Carey, at 120 (rated) HP, is not actually similar in power an original 1500cc 547 engine, as one might at first suppose. The reason?
The 547 was rated at about 85 ft-lbs at 5000 RPM.
My measly base 1915 makes 125 ft-lbs at 4000. That's 47 percent more grunt, 1000 RPM lower than the premier small displacement racing engine of 1955.
That's a huge difference on the street. (And of course a lot less power than those of you running 2110s, 2180s and 2332s can boast).
Frankly it's almost impossible for most of us to even imagine what a real 4-cam feels like on public roads, but it's fair to say that most of us, if we got to sample one and were being honest, would be disappointed.