Depending upon the year and engine source, 4.2L AMC/Jeep®/I-H version timing covers can be different than a 4.0L cover. The TDC mark may be many degrees away from the 4.0L damper mark, which is typically the damper used in a Mopar EFI conversion. Determine the true TDC for #1 piston when referencing TDC; this is determined by measuring the piston's position in #1 cylinder with the spark plug removed. The piston must stand at its peak when determining TDC.
Note: Inexpensive TDC tools are available at Summit, Amazon and elsewhere: https://www.summitracing.com/parts/sum-900189 or TDC