Noticed increase in horsepower The spark plugs work great, and I have noticed a growth in horse power, and startup time. It is running better. Thank you for shipping quality products in a timely manner. Denis, Verified Buyer Spark Plugs 5 2020-01-03T21:29:43+00:00 Denis, Verified Buyer The spark plugs work great, and I have noticed a … Continue reading Noticed increase in horsepower