1974 CHRYSLER, IMPERIAL & PLYMOUTH Body, Chassis & Electrical Service Manual [eb5146R]
From Bishko Books, Repair Manuals, Owners Manuals, Parts Books & Sales Brochures
They have both print and digital copies.
The one I had 20ish years ago just had little plastic spikes to half-grip it into the carpet. The 20lbs of loose change in the bucket area also helps with retention.