Unfortunately the 5.0 Engine was never designed for racing fuel operation (c16, q16, E85, methanol 100 octane and octane boosters), the plastic secondary guides are softened quickly by chemicals contained in these fuels that eventually make their way into the oil past ring gaps to the point of failure as shown below. Furthermore increased valve spring pressure and load from aftermarket camshafts and cams place the part under extreme load. This causes secondary chain failure and ultimately catastrophic engine failure.
MMR has the answer for these applications with its new Heat Treated Billet steel guides. The MMR guides completely eliminate this problem. The MMR chain guides are lubricated by oiling holes to help minimize wear and ultimately provide reliable operation for both street and strip vehicles that are unable to run the factory plastic guide due to common failures. These guides are suitable and recommended for ALL Fuel types. 2 Guides included for 1 engine. Direct replacement. Plug and Play.
2011-2023 Mustang GT
2012-2013 BOSS Mustang
2011+ Australian 5.0 Models
*This is a heat treated steel part and moisture or human handling can cause minor surface rust (like a brake rotor), This does not affect performance of the item in ANY way and is no cause for concern. This item can show minor heat discoloration and wear pattern after initial break-in due to metal on metal friction and is no cause for concern. Chains Must be submerged in oil prior to installation onto this part.
THIS ITEM WILL NOT FAIL LIKE THE FACTORY PLASTIC GUIDE BUT DOES INCREASE STRESS AND WEAR ON THE SECONDARY CHAINS AND THERFORE THIS ITEM IS NOT SUGGESTED FOR CONSTANT STREET USE. IT IS SIMPLY DESIGNED AS AN ALTERNATIVE TO THE FACTORY PLASTIC GUIDE WHEN THERE IS NO OTHER OPTION DUE TO PLASTIC GUIDE FAILURE! THIS ITEM IS BEST SUITED FOR DEDICATED DRAG VEHICLES AND THOSE VEHICLES THAT SEE LIMITED STREET USE.