What is diff in spark plugs?

[spincast375]

We currently have an AC Delco R45TSX spark plug in our 454.

The standard AC Delco is an R44T.

At Autozone, they also offer a Denso Iridium, an AC Delco Rapidfire, and a Champion Double Platinum.

Can anyone explain the difference in these, and what is the optimum plug for this engine? The 84 Blazer is a dd, but will do some muddin'.

Thanks.

 

[Thunder]

Just use the AC Delco R44T. IMHO The best plug made for a V8 truck with older style (non DI) ignitions. if you have a newer style. distributorless ignition the AC Delco Rapid fires work good.
The other plugs you mentioned are high perfomance modlels designed to extract the most hard earned money, as fast as possible out of your wallet.

 

[Bigg R]

Autolite makes the best plugs for a GM, they last a lot longer than AC's!
Never use a Champion in any thing but a lawnmower!!!!

 

[MudFrog]

I had the el cheapo autolite's in my blazer then switched to the Bosch Platinum 4's and noticed big difference. Now my blazer is just a little sluggish, before it was really sluggish

 

[5kerblaz]

I've messed a bit with coils and plugs in the seven years I've had my '87. Stock AC plugs (.035)/stock coil. AC RapidFire (.045)/Stock coil. Autolite copper cores (.045)/Jacobs coil (Jacobs said, "don't use platinum or any other hipo plug." Now I'm back to Autolite copper cores (.045)/stock coil and my truck runs great. I agree with the earlier poster, they're just trying to pad their wallets with yours. I'll stick with copper.