How's it going guys? As many probably already know, my engine was just finished being built, and I will be getting it back tomorrow. The only problem is that these domed pistons might hit the spark plugs.....at least from the looks of it (so says the guy who built my engine). I was wondering if you guys could tell me what spark plugs I should use to deal with this little problem? The setup is.....

333
edel Performer rpm heads
speed pro .100" domed forged pistons

I know this is kind of an oddball question since I can't really give specific details, but I just thought that maybe there are certain spark plugs that were designed for a situation like this? I'll call Edelbrock tomorrow and see what they have to say. If I were to put the plugs in and turn the engine over by hand wouldn't that tell me if there was enough clearance? I mean as long as they don't hit, then things should be fine right? :confused: I'd appreciate any advice that you guys could give me. smile.gif

Thanks
Ben

You can always run a plug without a extended tip. Or a non extended tip plug that you index so the open gap is toward the piston dome. The piston/rod may grow .035 at rpm so just because it doesn't hit when you crank it by hand doesn't mean it will clear at 6 grand.

I'm not sure what engine you're running but I have .100 dome Speed Pro pistons in my 454 with Edelbrock heads. The block is even 0.0 decked. I run the recommended plug which has a projected tip. I think it's Champion RJ12YC.

How do you go about indexing a plug? So a plug that doesn't have an extended tip couldn't get in the way of the piston then? I think I know what you're talking about, but would you happen to have a picture of a plug without an extended tip? Sorry about all the questions.....just trying to understand. Thanks

Originally posted by 71chevy0192:
How do you go about indexing a plug? So a plug that doesn't have an extended tip couldn't get in the way of the piston then? I think I know what you're talking about, but would you happen to have a picture of a plug without an extended tip? Sorry about all the questions.....just trying to understand. Thanks You draw a line on the plug continuing the ground strap line. Go through various plugs and find the ones that tighten up with the line where you want it.
Moroso makes washers of various thicknesses that you can use to get a plug to line up.
I had a 357 SB that I had JE make. 14-1 w/ 67cc chamber. .600 dome and a very thin fireslot. The heads called for a 13/16" reach gasket plug. They all hit the porcelin if not the ground strap. I ended up having to use a ext. tip 1/2" reach plug with the ground strap between 11:00 and 1:00 other wise it would hit