For most collectible, classic cars, replacing original equipment (drum brakes) with modern equipment (disc brakes) will significantly lower the value of the car unless the change is easily reversible (Petronix back to points) and the original parts are retained to be sold with the car. Usually people do not carry this to an extreme, for instance, if you used a different set of points in the distributor.
I have served as a national concours judge (not for Continentals) at a number of different events and the standard is always to compare the car to how it would have been delivered from the factory. Any deviation (and the standards vary dramatically from organization to organization) from original would cause a deduction. Some organizations allow safety exceptions, e.g., the installation of seat belts if the work is done to factory standards.
Usually, concours quality cars will draw the highest prices. However, some restomods that are exceptional will draw exceptional prices. I try to keep my cars as close to original as practical since the 50s-60s cars were designed to be driven at speeds somewhat comparable to today's traffic and I tend to drive the older cars a bit slower than my modern cars. However, I will sacrifice some originality to use radial tires.
As always, just my opinion and I am sure others will have different and equally valid comments.
Larry
Larry Durocher
1956 Mark II C5601429
1962 RR Silver Cloud II drophead
2006 Ford F150
2010 RR Phantom drophead
2013 Bentley GTC
2015 Lincoln MKT