The crankshaft sensor shold be on the engine block about midway on the back side.
take the oil pan off and everything around it you will see it take the chain off take the pistins off and replace
set timing on 1991 c2500 5.7 liter
1991 probably doesn't have a crank sensor, it probably has a reference in the distributor.
where the map sensor on 98 blazer?
No.
no
the o2 sensor is located on the exaust manifold
That year did not have a MAF sensor / Mass air flow sensor.
sould be on the manifold
50 to 60 lbs
Haynes makes a manual with the wiring schematic for the O2 sensor on a 1991 Chevy Blazer S10. The manual can be found at most book stores.
Chevy-GM 5.0 liter is 305 CID.