i have a 74 dt 360. when you hold the throttle wide open it will only reach about half throttle and never wind out. you can hold the throttle wide open for about 30 second in first gear and it will finally start to wind out. once i get it to wear it will wind out as long as i stay in the throttle it runs great. if i let it drop back down to idle, the whole process starts over and i wont wind out again. any info?