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. 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.

Gm inline 6 casting numbers