Retrofit Trunnion Kits are available if you reuse the stock arms. The trunnion bearings in the stock rocker arms are another known weak point. It includes intake, heads, exhaust, torque converter, rear-end gears, etc. This is not just Valve Springs and rockers. Just match the other parts you choose to support it. LS engines respond extremely well to Cam Swaps. Less space around the valve can limit the air flow.Ī 4-Corner Steam Kit can reduce hot spots that can cause #7 ring end gaps to butt. This means that the valves will be closer to the cylinder walls. The LS3 heads will fit on any LS block with a minimum 4.000 in.
#LQ4 PRC2.5 HEADS FLYCUT PISTONS INSTALL#
Various combustion chamber sizes are also available.Ī popular upgrade to the LQ4 and LQ9 is to install a set of LS3 heads and intake. Aftermarket heads offer a range of intake and exhaust runner volumes. There are also many Aftermarket Heads available. Lightweight LS3 valves can be cut to fit the seats and performance valve springs can be installed to decrease valve float. Having the stock heads CNC machined will improve air flow and power. Performance Rotating Assemblies are also available. Upgrading to a Forged Crankshaft early in your build will save you the headache later. However, if you plan on using boost or nitrous, get Forged Connecting Rods.Įven though it is cast, the crankshaft can handle about 900 hp. A set of Forged Pistons should be high on your priority list. They have a history of cracking around the wrist pin and the top ring land. The stock pistons are a known weak point of these engines. The cylinders can be safely over-bored 0.030 in. There is no replacement for displacement. (You may need to lower the compression to run with boost.) Upgraded components will also perform better and last longer.īelow are some other upgrades that will improve the performance of the LQ4 and LQ9 engines.
![lq4 prc2.5 heads flycut pistons lq4 prc2.5 heads flycut pistons](http://i337.photobucket.com/albums/n364/jdawg4545/LS1%20Swap%20parts/IMG_5134.jpg)
However, you will need to upgrade the internals to handle that kind of power.Ĭhanging pistons and/or cylinder heads will allow you to change the compression ratio. True LS6 heads will have the stainless steel hollow-stem valves.On a stock engine, the following upgrades can improve performance and fuel economy: Remember, not all 243 heads are LS6 heads, but all LS6 heads are 243 castings. Also, the early perimeter-bolt heads (933 and 806) are far less desirable. You may even find 873 castings from the early LQ4 engines, but they are iron and not worth bothering with. On the truck side, these would be 035 or 317 castings (LQ9/LQ4) and featured 71cc chambers. 243 castings are harder to come across and are sometimes called LS2 heads. Aside from the casting number, they have distinctive D-shaped exhaust ports. 799 heads (65cc chamber and 210cc intake runner) are pretty much 241 LS6 heads worked over for truck engines and thus are a real treasure to find when hunting through boneyards. These are best for high-compression builds and really need larger valves and porting work. Other heads you'll run into are 852 and 706 castings, which have smaller 61cc chambers and 1.89/1.55-inch valves. The LS1 heads have 67cc chambers with 2.00/1.55-inch valves. 241 castings (the casting number is found near the corner of the head) are the most common since they were used on every 4.8L and 5.3L truck engine as well as the early LS1s.
![lq4 prc2.5 heads flycut pistons lq4 prc2.5 heads flycut pistons](https://i10.photobucket.com/albums/a130/Dougs68Camaro/LQ4-1.jpg)
Any intake manifold (LS1, LS6, LS2) will work with these heads as well as Vortec intakes from cathedral port headed variants. Due to the long cylinder sleeves LS2 blocks are great for stroking, a 4.000-inch crank will make a 408.ĭebuting on the LS1, the cathedral port heads were named for the distinctive shape of the intake port. For example, the cam sensor moved from behind the intake to the front timing cover and the crank sensor changed from black (24x) to grey (58x). Sensors also moved around and changed a bit. Provisions for active fuel management were added to most of the blocks and the bore size increased to 4.000 inches. While there were vast differences between the Gen II V-8 and the Gen III V-8, the differences between Gen III and Gen IV engines are nearly unnoticeable at first glance. Depending on the year and platform, the LS2 could have come with either head. The increased displacement meant more power and the increased bore meant it works with LS1/LS6 heads as well as the newer LS3/L92 versions. Early LS2 engines had 24x reluctor wheels and 1x cam sprockets while later ones transitioned to the 58x reluctor and 4x cam sprocket arrangement. It also found its way into the Trailblazer SS (395 hp) and the Holden sourced 2008 Pontiac G8 GT (361 hp). The LS2 debuted in 2005 in the Corvette (400 hp), GTO (350 hp), and the concept-car-inspired SSR (390 hp). The LS2 (6.0L, 364ci) was a large evolution of the platform and was given a Gen IV designation.