The only new replacement springs that I found that were compatible. Available here and in limited quantity.
https://www.marineengine.com/parts/omc-parts/omc-boat-parts.php?year=1987&hp=5.7&model=574AMFTC&manufacturer=OMC+Stern+Drive§ion=Distributor+-+Prestolite+Ibm-7013c
Originals...