Will Bosch Platinum 4 spark plug 4458 fit my Chevy S10 with 4.3L engine?

It will depend on if that plug was built for that engine. If you use the specific Autolite spark plug for that engine they will work.
Spark plugs are designed to fit specific engines so the wrong plug can actually be bad for the engine.

best advise is call a parts store or two

.054 inch.

If you buy new plugs that are correct for your car, they normally come pre gapped (particularly platinum and other 'non copper' plugs). I like to run 36/1000 or 0.8mm. But 1.1mm (43/1000) is also common.

This would equivalent to OEM
Iridium spark plug
Bosch part #9614 around 6.99 each

You can run other Bosch plugs from copper and up but you car calls for the iridium plugs hope this helps..
Dennis.....

If you need further help, reach me via phone at https://www.6ya.com/expert/dennis_f849d3d6a68c6430

Premium performance offered by Bosch platinum plus and also has excellent value while the Bosch platinum-Ir fusion delivers ultimate in spark plug performance and long service life.
http://autoplicity.com/manufacturer/95-bosch-spark-plugs.aspx?categoryid=53

Chrysler Voyager seem function well on Champion spark plugs. I had the same issue and only after buying Genuine Champion Plugs, the car resonded with power

These engines use platinum plugs-you don't gap these type of plugs because you will damage te platinum electrode and cause misfire problems. Make sure you use bosch platinum factory recommended plugs and if he vehicle has more than 75k i would recommend replacing your plug wires as well/

If you are talking about Bosch Platinum +4 plugs, then yes they will fit, but if you don't have a high powered (racing) ignition system, they won't do you any good, and might hurt your engine. Bosch Platinum +2 plugs will do an outstanding job with a newer factory ignition system, and save you some money.