This can be solved by looking at pictures. The 190 has a dome that extends from the valves to the spark plug side of the piston. It's circular. The Magnum combustion chamber has a small squish pad between the plug and the outside of the cylinder. The KB190 dome is 0.080" above the upper edge of the piston. So, any chamber like the Mag head will have interference. It will not bolt together and run. The valve placement and angle are the same for the LA and Mag heads, or very very close. It's not the valves.

The KB190 appears to be made for an LA head. It is definitely made for an LA block, deck height 9.599". The Mag block is 9.577. The compression height of the 190 is 1.675". Add that to a 6.123" rod and 1.79" half of a stroke and see what you get. It'll stick out of a Mag block. But that can be taken care of by the head gasket. The Mag squish pad is the problem. The dome would have to be machined off in that area. See Jeg's picture of a typical Mag chamber: https://www.jegs.com/i/JEGS/555/514200/10002/-1
Now the KB190: https://uempistons.com/i-28053-1-set-kb190-std-1-set-4000am8-std.ht

Or, you could call Edelbrock and ask them!
R.