You just have a hx40 with a 16cm housing. That is the best spooling hx40 available. A hx35 housing will not fit on a hx40 FWIW.
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1997 Dodge 2500 4x4 Ext cab LB 5 Speed, K&N BHAF, 5 inch turbo back , plate MIA, AFC tuned, bd 64/71-14, SDX 5x16s, boost elbow, 4K GSK, ARP head studs, oringed head, valair 13" full feramic clutch, autometer boost and pyro.