ACCEL140043-8 Supercoil Ignition Coils - Yellow, 8-Pack

Bottom line first; these were not a direct bolt-on fit, I needed to go to the hardware store and purchase 0.5inch spacers and 0.5inch longer bolts. These work great; increased throttle response (horsepower/torque) and increased fuel efficiency (2-4mpg), exactly what I was looking for.Depending on which website you go to you will get conflicting information as to the fitment of these coils. My application was for a 2004, Chevy Silverado 2500, 6.0 liter. Many sites said these would not fit, but they looked as if they would. When searching using the engine’s information (LQ4, Gen III) vice the vehicle’s, many websites said these would fit. But as stated above, it was not a one-for-one replacement. Spacers and longer bolts were needed.If you are looking for aftermarket coils for a GM product… be sure to check the brackets and part numbers. There are at least two different types of OEM brackets for the LS and LQ series engines. Searching strictly by vehicle info can and will be frustrating. Research your engine’s specs and go from there. But don’t be surprised if you need to do some slight modifications on your own.

I swapped these onto an LS1. They aren't a direct bolt on, but with the brackets available here on Amazon and the spacer kit they will fit. I was averaging 14.6 mpg before the coil swap. With the new coils installed my mpg went to 17.3. I only changed from factory coils to these accel coils. No other modifications or plug changes. There is a very noticeable torque increase over the stock coils, and the throttle response is better. I have no idea if they will last since I just put them on, but right now, I'm impressed.

2001 Chevy 2500hd 6.0Wouldn’t fit in the original mount brackets for square coils.Used new hardware, M6-1.0 35mm flanged boltsWith 1/2” spacers. Sits well all harnesses fitCoils work as designed.

Had mechanic install cause hybrid is little harder. Drivers side was easy, passenger side was hard. But work good and truck runs smooth.

These do not fit a 2006 Hummer H2

Well I was going by Amazon says that it would fit my vehicle even after it filtered for my vehicle but once I received I got depressed when outside of box didn't have my year but had to be sure so tried 1 and it didn't fit so please fix your filter process so less returns of big money items.

These coils are unreal. I have never replaced a coil or coils on any vehicle that gave me any noticeable HP gain. I always just assumed it was an advertising gimmick but not reality until now. My trucks throttle sensitivity and it’s launch when the gas is applied is amazing. It took me by surprise and it was like I was driving a different vehicle. I would strongly recommend these to anyone running stock coils. I waited for the price drop so I ended up paying about half off what they normally cost but had I known the difference they would make I would have paid full price awhile ago.

Replaced my stock coils due to rough idling with these accel coils. I did however need to upgrade the mounting brackets for these style coils. They definately give you that extra "push over the edge" kick. I had installed E3 spark plugs prior to installing these coils and already had a boost in performance with the plugs alone. Then installed these and it was night and day. Unplug the battery to reset the memory in the Pcm before you road test.

Easy mod to install and looks great on my engine.