I'm still working on plans to get an np241 in my 84 Jimmy. I have leads on one with mech speedo(from an 89 Blazer) and one with VSS(from a 90 Blazer). There's ups and downs to both, so I'm at a draw. Tell me, in your opinion. Should I source out the 89 241 and use a converter to hook up an aftermarket speedo? Or should I source the 90 241 since most aftermarket speedos state they use factory vehicle speed sensors? I know I'm missing something here. Please help me fill in the blanks.