I purchased a 97 7.3 last two years ago for cheap and have done some minor repairs since including new injectors. With 290,000 miles on the truck it was obviously time. After replacing the injectors i still had a moderate 'cackle' at idle and rough idling, after thinking really hard and some extensive research and reading mixed reviews i decided to give the HPX a try, needless to say the results blew me out of the water and my rough idling and cackling has dissappeared, I also noticed better throttle response and slightly easier shifting. Great prouduct for the money and would recommend to everyone, riff raff has never let me down.

Easy to install, and noticeable difference in the sound of the truck before and after. Very happy with this product

Installed in minutes, perfect fit, and it really quieted down the engine at idle and working! Would definitely recommend this product to everyone!

Perfect fit, smoother idle, 2 decibels quieter. I would buy not for performance but longevity on your motor

Quality materials to build a quality product.

Fast shipment easy install performance as promised will be ordering more items from riffraff. Highly recommend product and vendor

Excellent product, exact fit easy install. I’ve made my own (2 other 7.3s) using flexible hydraulic high pressure line but this product is superior in that it takes less room and is easy to install.

Install went very smoothly, did it in about 15 minutes after work. Off idle performance seems a little better. Most definitely a lot quieter which is the main reason I purchased this product. Idle is smoother and quieter and much less engine noise at cruising speeds. Highly recommended.

Direct fit. Great product