Greg, another thing to note (since the new genuine coils are quite expensive) besides aftermarket, you do have the option of pulling a used coil off of any general 148cc briggs, be it a vertical or horizontal shaft made between say 1983 (when they brought out magnetron) to about 2011.
All the ones (for example 3.5 classic, 375 sprint, 450 series, etc) all used that #420 coil from memory, and if you time it right you could probably pick one up free.
Note - Quantum is different
