Autolite 2150 Ford Motorcraft Pump Diaphragm open coil spring type   P/n APD434

This diaphragm has an open coil spring and .880” stem length

The 2150 pump diaphragm is 1-1/2" square.
Wire diameter this coil is 0.050” dia.

Carefully compare with your existing diaphragm 

Diaphragm with closed coil spring [0.047” dia.] is P/N APD342

APD342 on left – closed coils            APD434 on right – open coils