Champion L-78 Plugs
 

Not to further pummel an already deceased equine, but I've got a question about spark plugs. The last time I was down at Hershey I picked up a brand-new 10-pack of L-78 Champions from a guy. He said they'd work perfectly in a flathead V8. They're made in the U.S.A. and only cost me a couple bucks. Have any of you guys used these plugs before? How does the heat range compare? Right now I'm running Champion H-10Cs.

http://i1096.photobucket.com/albums/...rk%20Plugs.jpg

I did a test with an old (and VERY rusty) 81T cylinder head I had lying around. The L-78 (right) projected a good bit farther into the combustion chamber than the H-10 (left), which I think is good, but do they reach too far and kiss the valves? I do not have a depth gauge handy to measure the clearance. As for my car's engine, I don't believe the 59-AB heads I'm running have been milled; the cam is stock as well.

http://i1096.photobucket.com/albums/...ion%20H-10.jpg

http://i1096.photobucket.com/albums/...ion%20L-78.jpg

Re: Champion L-78 Plugs
 

The L78 looks just right.
The H10 is too low.