I've got a 97 Blazer 2WD LS, 4.3, and getting ready in the next month or two to do all the general maintenance. Putting in MSD 8.5 plug wires, new MSD coil, Accel distributor cap, new 02 sensors, the works.
I'm trying to decide between spark plugs though, At the moment, I'm kind of stuck between NGK (TR55 I think), and AC Rapidfire 12's, before this Blazer I had a 4.3 S10 and have used them both with no problems, though mostly I stuck with NGK. Which ones would be better for my Blazer, or is there a better choice?
At the moment no mods have been done, though later am planning for CAI, Flowmaster single in-dual out 40 series exhaust, and possibly an MSD 6AL box, and probably lower temp thermostat. (180 degree).
Unfortunately with reduced hours at work, waiting for bonus checks kinda sucks, so tying to get all the parts picked out/planned ahead of time.

Thanks!

 

If you browse through the threads you will find that most of us recommend sticking with AC/Delco for ignition parts on these trucks. I doubt that you will see much, if any, benefit with the MSD coil since the system on your '97 is a pretty high energy system as is. Non-AC/Delco O2 sensors have caused problems for others. Just things to consider.

 

good to know

 

If you install a 180 degree thermostat you will hurt your gas mileage and soot up your O2 sensors.

 

Good to know, was just kind of carrying over everything I knew/did for the 4.3 on my S-10 to my Blazer, assumed things would be the same. I think the only 02 sensors my local shop listed were Bosch, but I'll have to double check, and there's problems with Bosch??? I guess I'll keep the thermostat the same then... I'd always stuck with Delco plugs for GM motors, especially V8's, but a lot of guys on the S-10 forums had good luck with the NGKs, and I never had any problems. Someone at work recommended Bosch Platinum +4, but I'm staying away from those for now, not convinced on them yet...

 

Don't do the Bosch plugs. I made that mistake the first time I did my tune up on my truck and it was horrible. Try to stick with the recommended plugs.

 

Yeah I made the mistake of bosch plugs also I took them out after like 900 miles they were worse than the old ones. Also many people have had issues with the bosch O2 sensors they are know for not responding properly right out of the box.

 

Well, unfortunately, none of the parts shops where I am stocks Delco 0² sensors, I've got my choice of Bosch, Bosch, or Bosch and Denso...
I wonder if Jegs can get them? I know they stock the Bosch sensors.... Most of my parts will be coming from them anyway, cheaper that way, and they ship quick to me, usually no more than 3 days...
The Delco AFS105 is the right part number for the 0² sensor, correct?

 

Sounds right. Try RockAuto.com. They have them at a good price.

Also, check out ACDelco.com to see if you have an AC Delco retailer close by.

 

Ok, found them, next dumb question, because I'm seeing confusing info... Autozone says I need 2, 1 upstream and 1 downstream, RockAuto says I need 3, 2 up and 1 down, and I've seen some places say I need 2 up and 2 down, I haven't physically checked my Blazer yet, how many do I really need? I saw 2 when I did my oil change, 1 in the Y-pipe upstream, drivers side, and 1 down from the cat... is there another upstream on the passenger side somewhere?