Are you sure it's tire shake you're feeling? A 60' time of 1.35 doesn't sound like a tire shaker. My car goes low 1.20's and I've never felt tire shake. Could it be a trans or converter problem? I'd rule that out first, then go to the ladder bar setup. I have felt a sort of "multiple launch" wherein the car loaded and unloaded the slicks (chassis) repeatedly upon launch. I suppose it felt a little like tire shake, just farther apart than the rattle of tires. I cured that problem with a little more pinion angle down. BTW, my car is 2700 lbs., N/A BBF, Glide, ladder bar, 9 in., 32 X 16 slicks. Hope I've helped. Good luck.
The older I get, the smarter Dad was.