Spark Plug Query

[Jmclendon]

Hello all,
I'm off to the parts store today to pick up some spark plugs. Since the AC C44 plugs aren't an option, what would y'all recommend? They're for a 61 305D BTW

The AC Delco website has a handy matcher that tells me the 41-832 is an option.

Now, AC Declo isn't available over here. Funnily enough, when I use the NGK cross reference, there doesn't appear to be a match for the 41-832. But, it does say that a NGK B6S is a match for the AC C44.

Frustratingly, some of the cross reference sites I've looked at say that I can use a small engine (IE lawnmower) sparkplug. So yea, the internet is awesome.

Anyway, as always I'm open to suggestions.

[Jmclendon]

This is likey a dumb question. Buy, why are the spark plugs on 2, 4 and 6 on a 305 longer than 1, 3 and 5?

I've bought a set of 6 matching, only to realise that they're not fitting on one side (too short). But the other side fits fine?

[turbobill]

Maybe a head has been swapped from a different engine that used a different style plug.

[bobdylan]

You need some help, from some fellow Ausses, That may have your local market figured out. There is a guy I met this year at the Stove Bolt reunion in Riverside Mo. He came over to go to the truck show, his name is Tim Pryer. Tim Pryor Reinforcing Pty Ltd. Tell Him That You got his name from, Bob That had the V12 at the Stove bolt reunion. He is really a nice guy, might be a good contact

[Jmclendon]

Originally Posted by turbobill

Maybe a head has been swapped from a different engine that used a different style plug.

So, I'm not crazy for thinking this isn't normal?

[AZKen]

It also could be a previous owner mistake. I didn't know there were different heads you could put on that had different length plugs. I guess get head casting numbers and check here before buying/install two sizes. Not computing right now.

[Jmclendon]

So, you don't think it's going to cause any harm running one side on short plugs and the other on longer ones? I don't mind the minor oddity, so long as I'm not doing any damage to the engine.

I've been daily driving for a couple of weeks now and it's been running ok.... however, I had suspected the mechanic I went to didn't bother gapping the plugs that he put in (my suspicions were confirmed last night when I pulled them).

[AZKen]

I just looked at RockAuto site. They list a 3/8" length thread and a 3/4" length thread for the same 61 305 motor. Don't know why. Wait for a guru to reply with the answer. I assume both will be OK or Rock Auto is wrong. See if you have one of each length. Both gapped at .035/.036. Give us the numbers of the two plugs you have. Who bought the plugs? you, the mechanic, already had them in truck?

[FetchMeAPepsi]

It's already been experimented with (and by me too) - either plug will work fine. Once we thought the long plugs would hit the piston head too, but it doesn't. You can run both and be fine, though it will be funny if you forget this thread when you go to replace them!

[Jmclendon]

What I can't make sense of though is why the shorter plug won't fit into the 2 4 6 side of the engine. Is what turbobill suggested the most likely cause? Someone has swapped a head at some point?