There is a very noticeable improvement in performance after torquing the intake manifold bolts to proper OEM specs. Mine is 2020 Challenger R/T with less than 1100 miles on it. After doing some cleaning under the hood, I decided to check the manifold intake bolts. All bolts were nearly 50 in-lbs under spec! Either they are coming out of the factory under-torqued, or it is due to heat cycling. In any regard, tightening the bolts has improved low-end torque and overall stability. Runs smoother, tighter. Torque should be 105 in-lbs (or) 9 ft-lbs. I would use a high quality torque wrench the uses in-lb increments. I use only Snap-On torque wrenches. S-K and MATCO are good too. Tightening pattern:
I picked this up from a different Challenger forum. I was cleaning under the hood last week and figured I'd give it a shot.
