These heads have thicker decks to maintain headgasket seal. There are also many Aftermarket Heads available. Lightweight LS3 valves can be cut to fit the seats as well. 4.8L and 5.3L engines have small intake valves.
Having the stock heads CNC machined will improve air flow and power. Performance Rotating Assemblies are also available. stroke crank costs no more and gives you added displacement. Upgrading to a Forged Crankshaft early in your build will save you the headache later. The rod may require small-end honing to fit.Įven though it is cast, the crankshaft can handle about 900 hp. Most forged pistons use the original larger pressed-pin diameter. Keep in mind the original pressed fit and full floating pins had different diameters. Forged piston companies have offerings for both. If you go higher, get Forged Connecting Rods. A set of Forged Pistons should be high on your priority list.īoosted, the stock rods will handle about 700 hp. 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. This prevents the piston from rocking at BDC and scraping up the skirts. When stroking, choose a piston with a minimal skirt taper.
The iron blocks have slightly shorter cylinder lengths than the aluminum blocks. stroke, displacement can be as high as 383 c.i.d.
Although they can be bored to LS1 sizes (3.898 in.+), the extra thickness can help head gasket seal. LS1 and LS6 based performance parts are plentiful and many will bolt right on.īelow are some upgrades that improve the performance of the LR4, LM7 and L59 engines. They are also easier to find than the higher displacement engines. The biggest bonus of buying a 4.8L or 5.3L engine is the low cost.
However, you will need to upgrade the internals to handle that kind of power. The LR4, LM7, and L59 have very strong blocks. On a stock engine, the following upgrades can improve performance and fuel economy: