there were different front suspensions those years.
http://www.ply33.com/Models/PD/
http://www.ply33.com/Models/PE/
http://www.ply33.com/Models/PF/
http://www.allpar.com/history/plymouth/1934.html

For stock, go stock.
For a new rod, go aftermarket. example = http://www.streetrodgarage.com/1934plymouthstreetrodchassis.aspx
For a traditional 50's rod, it's tougher.
Fenderless or fendered?
The parallel leafs would look the part, but it can't be lowered much.
The IFS would only work under a fendered car. = http://www.vapinc.com/mopar/Suspension%20Parts/main.html#anchor13264
You could also clip the front frame and mount a F%rd style front (transverse leaf/solid axle)suspension (check speedway and other rod suppliers).

another discussion
http://www.hotrodders.com/forum/need-ifs-help-1934-plymouth-34511.html

http://www.jalopyjournal.com/forum/showthread.php?t=238290

http://www.jalopyjournal.com/forum/showthread.php?t=81110