Re: vibration maintaining cruising speed
I have this, I think, but in my case it is right around 40mph. It's like a harmonic distortion/low rumble and what you describe with giving it a bit more gas alleviates it - though if the speed limit is 40mph that is not much of a solution ha!
I suppose the same suggestions apply, even though I don't have a 700r4 but a TH350 (with 2 piece drive shaft) ? I wished I had a 700r4!
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Richard
'72 Chevy C10 Cheyenne Bronze on White [Hook 'em Horns] 
SBC 350 | TH350 | LWB | Buddy Seats
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