[32phil]

The Death Wobble causes and cures has been beat to death ( sorry) on this forum and the Jalopy Journal.
My take on it is:
On a stock Early Ford.... level chassis, same size tires all around etc., the cause for the death wobble is usually worn parts combined with adjustments (toe in/out ) out of spec.
Rebuilding a stock front end and doing the proper adjustments including tire pressure will usually cure a STOCK car.
On a MODIFIED car......rubber rake ( big N little tires) dropped axles etc.
IMHO the cause is a change in caster.
In many cases.... the front end is brand new/rebuilt and the adjustments are correct, with the rear of the car rotated up the caster changes and causes the death wobble.
A steering damper will help as it will slow down the side to side oscillations.
All the pat answers of worn parts, alignment, radial or not tires, tire pressure etc. will help.... but will not cure it.... on a MODIFIED car unless the caster issue is addressed one way or another.