Setting timing is done by loosening a bolt below the distributor and rotating it. I have the '63 specs - the '64 should be close if not identical. The timing for a 144 six is 8* BTDC, the 170, 6* BTDC. There is a timing mark on the front crank pulley and a tin plate with markings 0 to 14 on it bolted to the engine just above the pulley. They are often real cruddy and need to be cleaned up - and often a chalk mark thru the crank marker is needed for it to be seen Check the points as well - gap is .025 with a 35-38* dwell angle, plug gap is .035. Idle speed is 500rpm

The shudder when going thru the gears is most often oil from a leaky rear engine seal. You either fix it if too bad or suffer the shudder if the oil puddle on the driveway is small . It can also be a worn out clutch disc, broken springs in the disc itself or an overheated and heat checked/warped flywheel. The pressure plate springs can also have failed or the iron facing warped or one of the three pressure plate actuating levers bent .