RE: Timing Chain???
If and when you do change this out, I would go with the DBL not the single. I upgraded this in my 350 when I rebuilt it and its still within .002 of new and 115,000 miles on it. (checked it when I replaced the timing cover gasket due to I changed out the cover).
On any car/truck/suv I get that has over 140,000 I change out the timing chain/belt just for peace of mind.
1996 S10 Blazer 4 dr 4.3, vin W (work horse)
74 W200 4x4 360/727/NP205 D44/D60
1988 G20 Conversion Van
92 Honda Accord (daily Driver)