spark plugs

[sspano01]

hi folks

on my list of small items to-do this winter (oil cooler, better springs) - i'll swap out the spark plugs. i was running 'stock' autolite plugs from a lincoln with a 460 in it.

i have a 521 (429/460), aluminum ford super cobra jet heads, msd 6al, and fuel injection.

any suggestions on what you all are using, somekind of "splitfire" fancy plug?
im sure i can squeak out another 1hp per cylinder

[Gofastoldguy]

I have been using E3's, no gap plugs for 7k miles without a miss. Get 22 MPG at 90-95 mph (Phx to Laughlin, NV). Around 7-8 dollar each but worth it.
BBryan

[Tom Wells]

sspano01,

I have a couple of "mild" street 385s, one 521 with Ford aluminum CJ heads and one 557 with Edelbrock heads and about 9-1/2 compression. One is EFI and one uses a Holley.

The CJ heads use SP-447 (AGSF32C) Motorcraft plugs just fine. I change them every 5K miles or so whether they need it or not

The Edelbrock heads use the Champion RC12YC plugs.

Each set is gapped at around .050" according to the MSD spec.

I've tried other "higher tech" plugs and regretted it every time. You may or may not have the same experience...

Tom

[Bob In Ct]

When installing the new plugs use a lubricant and a torque wrench (in-lbs). Aluminum heads can be easily damaged.

AutoliteSparkplugs.com

Bob

[bobcowan]

Sometimes a fancy plug will show a small increase on the dyno. And sometimes not.

Platinum and iridium are only there to increase longevity, not performance.

I use standard copper core Autolites in everything. You have to change them a little more often, but they're cheap, easy to come by, and reliable.

[scootter]

I also use the Motorcraft plugs and change them usually once per year. Cheap and work good. Mine is a slightly changed crate 514. I gap mine at 45.

[Dennis O'Shea]

I also use Motorcraft plugs I also change them once a year its a cheap way to get some piece of mind Oh wait I lost it a long time ago

[RET_COP]

NGK V-Power--with a small dab of moly paste on the threads.

[sspano01]

thanks for the ideas! maybe i will try the autolites with a larger gap setting? those E3's look fancy though

[sspano01]

Mr wells - your tag says your 521 has multiport efi. I'm running Holley throttle body, which is nice, but not as sexy as mpfi. Is that a custom setup or off the shelf. I do like a good hilbourne though

[Tom Wells]

sspano01,

It has a Holley 1000CFM throttle body with a modified Torker II with injector bungs and eight 50(?) lb injectors. I converted it to the Holley wide band O2 sensor several years ago, tuned it and pretty much leave it alone.

Look in my gallery on the first page and you can see a photo of the setup. Or here for more details: INDY gets his EFI :-)

Tom