In a weak moment I figured it's time to replace spark plugs in my '94 N/A. It still runs fine, but I know the plugs have at least 100,000 miles on them. I Bought the recommended Bosch platinum FR7DP's with standard center ground. The first plug I pulled was Volvo brand with 3 ground electrodes. The Bosch plugs are longer than the OEM plugs - by the height of the center electrode. So my question, is there enough clearance in this engine to run the Bosch Platinums? Or do I need to get the flatter multi-electrode style.

This isn't one for trial and error!
Thanks for any help.

Get your money back for those aftermarket plugs and just use the 3 prong OEMs that only cost about $9 a set at your local dealer. Don't install plugs that are longer than stock as there's some risk involved IF they aren't specifically made for your engine. The OEM plugs are very troublefree and 'claimed to be' better plugs won't help with anything.

If you got 100,000 miles out of Volvo plugs, what are you looking for, 200,000 miles?

I've seen many discussions about plugs on this forum, at least half the posters prefer OEM plugs.

I hope that someone can answer your question. You could make an indicator out of wire to measure clearance. Even if the plugs fit, I doubt that the extra reach will improve performance.

Longer plugs may be hotter and possibly cause preignition.

BTW - Click and Clack say "If you leave your plugs in for 100,000 miles, they are in there forever! Every two years you should remove the plugs and reinstall them so that they do not seize in place"
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3 8s & 2 7s 740,000 miles total