Hi there
I have a 67 camaro with a 350 , a rebuilt 700r4, 69 nova posi rear end new axels, and multi leaf srings, new driveshaft,new flexplate and new torque converter.The vibraton starts at about 35 mph only in the split second when I push and let off the gas pedel. When I get to about 53 mph the vibration is constant also over 35 mph if I place car in neutral the vibration is constant. Any advice?
Thanks

 

Check your driveshaft u-joints

 

Is your driveline angle set right?

 

check you drive shaft u joints and check to make sure they are centered in the trans and rearend mounts. If that does not help pull it and take it and have it spun to make sure it is ballanced.

 

new driveshaft needs balancing.