The incredible traction, helped by sea air rolling into the area, kept the track surface just moist enough, so it became super tacky. It gave the West Coast riders the advantage, who knew the setup and fast line. Rumors say top riders watched the tide tables, and if there was a full moon, they would anticipate how that would affect the traction.

In the 1960s, one racer got the advantage by hardening the venerable Pirelli 4:00X19 MT53 at Ascot. He and a few other riders realized the older tires they had previously used worked better because they were very hard. In fact, the tires were so hard they had to use a grinder to "cut" them. 

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The first Sonic Weld frame was made of 4130 chrome-moly, it was light and became very popular, especially among the 1968 Ascot Pro novices running 250cc machines. Most of the Sonic Weld frames produced were nickel-plated and looked really good. Later, they built a complete 4130 swing arm frame. The first one was for a Triumph 500 and went to Gary Nixon. During this period, Hensley moved his production to another location and took Kastan with him to form Trackmaster Racing frames.

Timing was good for Trackmaster because at the same time, Junior and Expert engine displacement went from to 500cc OHV to 750cc. The rule change caused a flurry of activity for racers nationwide to get ready for the new season. They had to build an all-new flat tracker based on the new rules. Trackmaster was perfectly positioned to provide the ultimate flat-track chassis and did so with the first purpose-built, dirt track racing frame. Initially, Trackmaster frames were available "frame only" or with all the necessary hardware for assembly. Later one could get a tank, seat, fender brace, forks, and pegs/brake pedal, all designed to fit perfectly on a Trackmaster frame.

Triumph offered many performance engine parts and factory racing recommendations/specifications, including a drop-on 750cc top end kit, for the 650 unit engine. Other specialty performance companies (WEBCO, Megacycle, Barnett, ARD, etc.) had many proven performance parts and accessories for the Triumph 650. Combined with the Trackmaster frame "kit" and wide selection of performance parts for the Triumph unit 650, one could pretty much assemble a very competitive race bike. Triumph Corporation sent a bulletin to their dealers recommending contacting Trackmaster frames directly, creating strong demand.

At the same time, AMA flat track was going through monumental changes. Other tire brands followed suit with the introduction of the larger, flat track-specific tire (Goodyear DT). The new tires offered improved traction due to size, compound, and tread design. Then AMA approved the addition of rear brakes as an option first (1969) and later became mandatory on all bikes in all classes in 1977. AMA Class C racing was based on racing production models. The rule was that 200 models of the homologated bikes were to be in the factory's warehouse for AMA inspection and verification. Later, AMA changed the rule from 200 to 25 models for verification.

All these new rules played out at Ascot. With all the changes happening, the sport changed almost from week to week. 1969 was the transition year when most of the top riders went to the 750s, but a few 500s were still competitive at Ascot. By 1971, top riders were on Triumph, BSA twins, and many of the other riders were on Trackmaster. Most were Triumph 650s with homologated 750 drop-on top-end kits. Later BSA homologated a 750 kit.

In the early 1970s, Linn Kastan started Redline Racing frames, and then Doug Schwerma started Champion. Yamaha USA actually sold Champion frame kits and offered engines through their parts department, sold to dealers. Many more custom and flat track frame companies were started during this time. Some people believe AMA racing was “influenced” by Harley, but during that period, most changes benefitted the British brands, primarily Triumph/BSA.

Harley had to quickly develop a competitive 750cc OHV 750 (the first XR750 was introduced in 1970). Prior to 1968, Harley had the flathead KR750 race-specific model that generally dominated AMA flat track for over 20 years. The new XR750 in its first years was successful with factory riders winning AMA flat track Nationals. Considering it was a first-year racing model, it performed well winning 10 AMA Nationals.

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In 1972, Harley updated the XR750 and introduced the alloy XR750. By 1973, with some notable exceptions, the XR750 dominated Ascot weekly half-mile races. However, the new rule allowed other brands to be very competitive at weekly Ascot half-mile such as Norton, and later Yamaha. Then Honda burst onto the scene with its RS750 V Twins in the 1980s. It later dominated with riders Ricky Graham and Bubba Shobert.