These are POLY motor mounts that fit 99-06 GM LS-equipped trucks including Silverado, Sierra, Tahoe, Yukon, Yukon XL, Suburban, Denali, Avalanche, and Escalade. They are a direct bolt up using factory hardware. These utilize a polyurethane bushing and 9/16″ bolt to isolate vibration from the engine to the frame while still being much stronger than factory mounts. These are laser cut 3/16″ steel fully mig welded. All brackets will ship raw ready for your paint or painted for a small fee. They match factory measurements so the engine remains in the same location as stock.
Yes these will work with the Hooker turbo manifolds. Although it is tight fit my mounts clear the manifolds with no modifications necessary.
Mount Height: This is a new option I added that lowers the engine 1″ from the stock position. This is generally only for the serious racer that has a good reason to do this. Lowering more than 1″ will require a lot of work. The main clearance items will be the steering line fitting under the oil pan on top of the steering rack, and the crossmember behind the engine at the bottom of the oil pan. A 1″ drop should clear these fine, but modifications may be necessary on your particular truck. The 3 main reasons for wanting to lower the engine will be:
- Additional cowl clearance for large intake or intercooler
- Lower CG and better instant center position for the suspension
- Improves pinion angle with lowered vehicles since it will raise the exit angle of the transmission
Lowered mounts are only sold in pairs.
The following only applies if you are doing a factory V6 to V8 Swap. If you already have a V8 ignore this section:
If you are doing a V6 to V8 swap you will need the V8 frame mounts from the same 2wd/4wd as your truck is. The frame side mounts are different for 2wd and 4wd and V6 to V8. My mounts are designed to work on the V8 frame mounts. The GM part numbers for the frame mount are:
15113847 RH fits both suspension styles
15113848 LH fits coil spring frame
15113849 LH fits torsion bar frame
Ronnie Trainham –
On my turbo 5.3 silverado setup, i would keep going through mounts every 5-6 months and even with oe mounts, the motor would seem disconnected from everything else and twist. I was initially worried that these would make my truck feel like a racecar and have absurd vibrations. Once these mounts were installed (less<1hr), i forgotten i had installed them 6 hours later. Literally no change in ride comfort, and if anything, it feels tighter to drive than it did before. Highly recommend for those who want the comfort of a DD but have some performance over oem mounts…
Dan (verified owner) –
These are awesome! I was hesitant to buy poly mounts since I had driven a car with solid mounts before and had a filling vibrate out. I bought these when I swapped a 6.0 with 224/228 cam into my 2005 RCSB. The cam is pretty aggressive yet there are no harsh vibrations or noises in the cab. I will never buy OEM mounts again Atomic is the best!
Brandon G. (verified owner) –
Perfect mounts, easy to install, and help with getting the right clearance for the speed engineering 1-3/4 headers (along with a energy suspension transmission mount)
Perfect for daily use have had mine on about a year now and they are just as good as the day I got them
And the AFP transmission cooler mounting bracket is worth it too!
Colten (verified owner) –
These motor mounts are badass. Major improvement over factory ones. And the better part is they’re made in America!