Olds Plugs?

[3XBrownCutty]

I was wondering what kind of spark plugs I should run in my 73-74 olds 350. I actually got some AC's (R46SZ) from autozone, but would rather take your guys' opinion over theirs. I read in another thread to gap them at .040, sound right?

Will be running a stock ignition, nothing special.

 

[dan2286]

Just use the ones you have, they will be fine.

 

[foxtrot]

If you're going with an HEI, I would go use a .060 gap...

 

[dan2286]

If you're going with an HEI, I would go use a .060 gap...

I am not positive, but I have heard plenty of people saying not to use that gap. I believe GM recommended it to help out emissions or something like that, it is not good for performance and it will prematurely wear out the ignition components(plugs, wires, coil, etc.) Most people like to use .040-.045.

 

[foxtrot]

I agree that a larger air gap will put more stress on the ignition system but don't agree that there will be less horsepower. Can you explain why there would be less horse power with a larger spark?
Thanks.

 

[dan2286]

I agree that a larger air gap will put more stress on the ignition system but don't agree that there will be less horsepower. Can you explain why there would be less horse power with a larger spark?
Thanks.

You are probably right. Honestly, I don't think ignition has a huge affect on power for a street car. If there is any differences, I doubt it would be noticeable.

Just ignore what I said about that :lol:

 

[3XBrownCutty]

Yup HEI, I'll try .040 and se how it goes.

Maybe I'll get some better plugs later down the road. Anybody have any good/bad experiences on aftermarket plugs?

 

[dan2286]

Yup HEI, I'll try .040 and se how it goes.

Maybe I'll get some better plugs later down the road. Anybody have any good/bad experiences on aftermarket plugs?

I have always had the best luck with ac delcos on my GM cars. I am sure there are good aftermarket brands, but I don't have any suggestions. One thing I can tell you is too stay away from those bosch platinum plugs that have multiple electrodes.

 

[jrm81bu]

As far as plug brand goes, I like AC Delco or NGK.

 

[3XBrownCutty]

Yeah, I've heard bad things about bosch too. I would've bought NGK, but they didn't have them in stock.