Satellite65
Well-Known Member
Had the same issue with my street driven '65. After correcting the pinion angle to 3* nose down, in relation to the crankshaft, problem gone. Based on your sequence of events though, it does sound like you have a driveshaft problem. Be sure that your shaft is not too short as well as being true and balanced.
Me too. At one time I had a '66 or later K frame in my '65 which pitched the trans tail down, equivelant to the pinion being nose up. Once I put the correct K in it, the driveline angles were correct and the problem went away.
I also had a light throttle cruise surge issue which caused a similar symptom. The carb (Holley 3310) was jetted a little on the lean side and at certain speeds the car would surge, vacuum would drop, power valve would open and richen up the mixture, engine would smooth out, vacuum would increase, power valve would close and the whole process would repeat itself. Going up one jet size on the primary solved that problem