Yep, that's always the first thing to check on any unknown engine. There's LOTS of clearance in the slant-6 because of the plug orientation (comes in from the side) and the ~1/3" negative piston deck height. The pistons in a stock 318 don't smack 'em. The pistons in a 2.2 or 2.5 don't smack 'em. Other applications? Check first!

Well, I finally installed the plugs and took a ride, you could notice a strong difference in performance. It doesn't stall anymore at idle, although you can still feel sometimes (but the less) that the engine misses something while stoping at a light. Bottom line: it got a lot better !!! , Thanks a lot Dan... Now I can squeeze a couple thousand of extra miles from my faithful and tired Slant.

I am going to check on economy, not sure if it got affected.

Ed.

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My other car is... another DUSTER!!! .·.