It's been quite a while since any serious attempts at boycotts of NASCAR events.
In 1965 when NASCAR banned the 426 Hemi engine from Grand National competition, Chrysler withdrew all factory teams and support from the series. Ford took advantage of the situation and won 49 of the 55 events on the schedule. Richard Petty spent the better part of the season drag racing. Richard and few teams did return near seasons end, without factory support and Petty managed 4 wins and David Pearson in a Dodge captured 2.
In 1966 NASCAR decided the new Ford "production" engine, the awesome SOHC cammer, would not be allowed to run. Ford said they would sit this one out. Ford relented near seasons end as several non-ractory Ford teams had been persuaded to run and were also sowing some success. Enough so that Ford was able to capture the manufacturers title for 1966 despite the boycott.
The most notable driver attempted boycott was in 1969. the drivers had forme the Professional Drivers Association in August of 1969 and elected Richard Petty as their president. The proclaimed purpose of the PDA was to improve track conditions for drivers and families, increase the purses for the events and obtain adequate insruance coverages for the participants. In Sepetember of that year Talledega's inaugural race was scheduled. In the weeks leading up to scheduled event drivers whoe were testing tires for both Goodyear and Firestone were alarming rates of failure. Drivers involved in the tests also reported that the track was far too rough for these speeds and needed to be repaved. Both tire suppliers designed and provided new tires, but testing still indicated the tires would never hold up to the speeds at the new track.
The teams showed up aat the track on Tuesday to begin preparations for the Sunday event. Practice was marred by further tire failures and many drivers were still complaing about the roughness of the surface. Richard met with Bill France and pretty much stated that unless corrections were forthcoming the PDA would not run the event. France did not relent on his postion and another meeting with more drivers in attendence simply led to another shouting match. On Wednesday the first day qualifying was scheduled and only 9 cars evena ttempted to make the field. Thursday qualifying session saw only another 4 cars make qualifying runs.
Both Firestone and Goodyear brought yet another tire to the track. After 4 lap tests of the improved tires, serious blistering was already present. The PDA said we won't race.
Things pretty much came to a head on Saturday night before the race. France had earlier stated that pretty much anyone who could get a car to the rack could race. As darkness fell an announcement was made over the PA that any drivers not planning ot compete, should pack their trucks and leave the property to make room for thsoe that would race. After a few moments a big rig fired it's engine and headed for the gates, the rig belonged to King Richard. In short order the line of exiting vehicles grew long and virtually every name driver in the series departed. Of the top drivers only Bobby Isaac remained.
The race was run the next day and won by one Richard Brickhouse. The PDA was never a significant factor in the following years.
There has been rare talk of boycotts since that time and never a serious threat for one to actually occur. At one time I do recall Cale calling for changes when the speeds at Daytona and Talledega had reached the stage where cars were literally lifting off the ground. No united front ever presented itself at that time that I recall. The last time I recall the subject was just last year. Some drivers concerned over safety at the restrictor plate races openly spoke of not entering these events. It was reported by someof thesse drivers that their sponsors had agreed that if the driver and team felt the danger of significant proportions taht they would support the withdrawal. Among those drivers whose names were at forefornt of this I most remember those of Dale Jarrett, Jeff Burton and Bobby Labonte though others were mentioned regularly. There were no withdrawals and NASCAR continues to run the plates, though with tinkering to aero, shock and spring packages. Many participants, scribes and fans fear the Plate races, but NASCAR rarely relents to these pressures. I doubt they would now.