6. With our baseline out of the way, of came the factory damper using a removal tool desig
Lucky for us, the Dodge Hemi and LS engine also have another thing in common. Cam swaps in the Hemi are as easy as they are in the LS, meaning you don’t have to remove the lifters to perform a cam swap. This is a definite benefit, as lifter removal requires head removal, extensive work indeed. Instead, Dodge engineers figured out a way to capture the lifters in place using plastic lifter guides (again like the GM LS family). All you have to do is rotate the cam and the lifters are pushed up out of the way and then retained by the guides, allowing removal of the cam. Of course, this can only happen after removal of the front cover, cam gear, timing chain and guide. Prior to our cam swap, we rotated the engine until number one piston was at TDC. The cam sprocket featured a timing mark which (at #1 TDC) was located at the 12 o’clock position. The crank sprocket was positioned likewise, but was not visible without removal of the oil pump. For reference, the crank key way (which is visible) was located in the 2 o’clock position. After unbolting the front cover bolts (don’t forget those on the oil pan), we removed the cam gear and set the timing chain aside. This allowed access to the tensioner/cam retaining plate bolts (access to the lower one is a tad difficult-but possible without removal of the oil pump) and rotation of the stock cam.
Previous testing has illustrated that the Hemi responds very well to aggressive cam timing, but it is possible to over cam an engine, especially a daily driver. The ideal situation for a cam swap on a daily driver is to ensure the cam upgrade improves the power output through the entire rev range. Big cams can provide a ton of extra power at the top of the rev range (especially on a Hemi), but these same cams often sacrifice low-speed and mid-range torque for that high-rpm rush. The reality is that a Hemi spends much more of its life in the lower rev ranges, even in spirited driving. Hemi owners should take that into account when considering the cam specs for a cam swap. Combining this with the fact that this engine was equipped with Dodge’s Multiple Displacement System (MDS), we installed a mild cam from the Comp Cams catalog. The 260H-13 (pt#112-500-11) cam offered .522/.525 lift, a 208/212 duration at .050 and a 113-degree lobe separation angle. There were a few smaller cams available in the Tri-Power Xtreme series, but this 260H-13 cam was the smallest offering in the XFI series. By comparison, the stock Hemi cam offered near .470 lift, 196 degrees of duration and shared the 113-degree LSA.
7. Next came the front cover to allow access to the timing chain, gears and oil pump.
The cam swap went off without a hitch, but we made sure to lube the new cam up thoroughly before installation. After reassembly, the engine fired up immediately, indicating that it was ready to run. The Comp Cam offered not only impressive power gains, but offered them through the entire rev range. Equipped with the 260H-13 cam, the 5.7L Hemi produced peak numbers of 401 hp and 427 lb-ft of torque compared to 370 hp and 407 lb-ft for the stock cam. Measured peak to peak, the cam swap netted an additional 31 hp and 20 lb-ft of torque, but elsewhere along the curve the gains were as high as 57 hp and 53 lb-ft of torque. Every bit as impressive was the fact that the mild Comp cam offered an additional 20 lb-ft of torque down at 2,500 rpm. Torque production with the new cam exceeded 400 lb-ft from 3,500 rpm to 5,300 rpm, or right where it can be put to serious use in a Ram truck. There are obviously wilder cams available, but it’s hard to argue with the extra 31 hp and 20 lb-ft of torque we got from camming our Ram. Check back with us next month as we take the 5.7L to the next performance level by adding a stroker short block, some ported heads, and more aggressive cam timing. For those serious gear-head, Ram truck owners, we will follow that up in part 3 with some boost.
8. We removed the single bolt used to secure the cam gear, then set aside the timing chain
9. It was necessary to remove the rocker shaft assemblies and pushrods to eliminate tensio
10. Out came the stock cam and in went our hydraulic roller 260H-13 from Comp Cams. The 26
11. After reassembly, the new Comp cam increased the power output from 370 hp and 407 lb-f
Power Numbers: Stock vs. Comp Cam
STOCK CAM: 370hp @ 5,200rpm, 407lb-ft @ 4,400rpm
COMP CAM: 401hp @ 5,600rpm, 427lb-ft @ 4,500rpm