I own both a Norton and a Laverda, I ride them both extensively. If you have the opportunity to buy A REAL Sfc fr a decent price, don't even hesitate one millisecond.
Now, an SFC is quite a different beast from a standard SF.
Engine-wise, it has a much lighter crank, diff rods, hi compression forged pistons, diff clutch, gearbox ratios are diff, the head is ported differently etc. Depending on the SFc series, you also have differences in the electric circuit, brakes, fork. The Sfc frame has reinforced engine lugs and some other minor variations. The last Sfc series has a lowered back frame, which for a very mysterious reason I have on my 1971 SF. Mine is a road bike with high compression forged pistons, hot cams, and Sachse electronic ignition. Great machine, but nothong like a real SFC, which is a true endurance bike, absolutely the best in the world at the time ine 1971-1972.
My Norton is a slimline racer with a hot 850 tilted commando engine, PW3 camshaft, Black Diamond valves and springs, Dunstall exhaust and full fairing, ported head with lightened rockers, balanced and lightened crank, Pazon ignition.
Both are great bikes to ride, the Laverda is by far the most reliable bike I have ever had. Didn't have to touch ignition, carbs or valves in the last 12000 miles. Zero trouble except for the starter engine freewheel which needs to be looked after. At 210 kg, compared with my Norton's 150kg or thereabouts, it obviously is less nimble, but stable as a rock at any speed. It will follow a Norton Commando Production racer driven in anger on twisty road with no trouble at all.
My Norton, besides the fact that it can be a bitch to start, is a truly fantastic bike. Faster and much ligjter than the Laverda. I took it yesterday to over 120mph on...the highway. Its ideal cruising speed on 1/4 throttle is about 85mph, at that point lightly twisting my wrist generates a thunderous roar from the Dunstall exhausts and an instant surge in speed that stretches my arms while the wind pressure tries to chop my head off. This engine goes.
Curiously, the Laverda, albeit heavier is much less tiring to ride than the Norton, even for long distances and more comfy...but the Norton has that waow factor...with an AP Racing vintage calliper and a 13mm master cylinder it also brakes very well, while the Laverda's big twin shoe drums are, hum, very pretty.