A quick study of the Dorman website netted this:
Under Head Length: 74.68
Knurl Diameter: 15.98
Shoulder Length: 14.99
Under Head Length: 78
Shoulder Length:1.008" (25.6mm)
Under Head Length: 73.4
Knurl Diameter: 15.93
Shoulder Length: 0.675" (17.15mm)
Am I correct in feeling that the 610-530'a 25.6mm shoulder will cause issues. The 610-509 also has a longer shoulder than the stock, but only by about 2mm.
There is also Dorman 610-565:
Under Head Length: 81.95mm
Knurl Diameter: 15.85mm
Shoulder Length: 0.4" (10.16mm)
This is practically 5mm short of the OEM course threaded studs.
Which is the better way to go?