turbo meaning like a 300 sd? go a year range for me?

I see 2 parts -

003 151 07 01 88 aka SR67X

and

002 151 69 01 88 aka SR61X

Can anyone confirm which one is appropriate or "better"

the SR61X appears to be listed only for the 81-85 SD's and the other one is said to fit all others w/ cast iron head 5 cyl turbo and non..