Re: 1929 Packard 626 overdrive

Posted by Owen_Dyneto On 2012/11/22 10:23:58

Just how fast to you intend to drive this car? With the stock rear axle you have a 40-45 mph car and this is probably approaching a reasonable limit for steering components & geometry, brakes, suspension, lights, etc. Remember, your car was engineered in an era when less than half the roads in the country were paved.

Of the two options, neither of which is inexpensive, the high speed gears of around 4/1 coupled with the smaller 626 engine a heavier body style will be fine in flat land but in hilly country you'll find yourself downshifting even on fairly gentle upgrades far more than you do now, an axle ratio of about 4.3/1 would be a better choice and perhaps add 5-10 mph to a oomfortable road speed. In that respect an OD with kickdown capability would be more convenient in hilly terrain but that would probably involve a frame-mounted OD lke a Mitchell and a split driveshaft.

I tour quite a bit in my 34 Eight with the factory 4.69 rear axle and I just limit myself to 45-50 mph, perhaps an occasional excursion to 55 and faster than that your pressing the limitations of the other systems like steering, suspension, brakes, lights, etc. With 80+ year old tie rod ends, drag links and the like which can suffer metal fatigue, that's about as fast as I want to go.

Changing rear axle gears will almost certainly be cheaper than an OD installation, probably by several thousand dollars though if you're knowledgeable in setting up ring and pinion gear contact you might consider doing it yourself. PM me if you want a shop recommendation in northwestern NJ near Easton/Phillipsburgh.