1960 Valiant - Should I Super Six???

Some like the 170 due to shorter stroke, it is able to reach redline quicker than 225. Mopar ran a modified Valiant 170 in a compact car race at Daytona in 1961. One week prior to the Daytona 500 drivers competed in a first-ever 150 mile "compact car" race. Lee Petty won the race contested on the 3.1 mile infield track in a 1960 Valiant with an average speed of 83.546 miles per hour. Among the modifications was a long ram manifold with a 4 bbl carburetor. The next year, same event, same results with a 225. NASCAR never attempted to run the event again.

Since your investment for the addition of the super 6 components is minimal, why not keep the 170 and try it. If you don't like it, move on to the 225.