LS4 Engine Overview & Architecture
GM threw us a curve ball with the LS4 engine, yet we were lucky to see a LS engine in these cars that would normally had a boring V6 engine.
The LS4 had unique difference because it was made to sit traversley in the car as a FWD setup. They were gen 4, 58X reluctor wheel, 5.3Lwith aluminum engine block. These engine did not have VVT, although they did have AFM (active fuel management aka DOD). The LS4 and LH6 where the first two engines that GM ever put AFM on in 2005. 2006 years adding more engine RPO codes with AFM. With this being said, all LS4 engines had AFM and never had VVT. These engines were found in Pontiac Grand Prix GXP (2005–2008), Chevrolet Monte Carlo SS (2006–2007), Chevrolet Impala SS (2006–2009), Buick LaCrosse Super (2008–2009) .
RWD Swap Challenges & Component Differences
When GM shoved this huge engine in this tiny space they had to condense the LS package which makes this engine not easily usable in a RWD car. One of the big differences was the crankshaft was shortened 13mm on the harmonic balancer side and 10mm on the transmission side. It had unique water pump and accessory drive, which non of the parts are usable on other LS powered cars. The bellhousing bolt pattern was made for GM's metric FWD transmission.
Next up, there is no starter provision on the block, since the starter is bolt to the FWD transmission. The engine mounting bolt bosses were also relocated.
Swappable Components & Upgrades
Now lets talk about what is swappable. The cylinder heads are usable on other LS engines and were cathedral port with the standard port shape and intake manifold bolt pattern. The intake manifold is also usable and can be flipped to a standard LS configuration of the Throttle being above the water pump (not the transmission side). The 76mm throttle body was smaller with a unique bolt pattern and came with a 8 pin wire connector on early years then switched to the newer 6 pin connector. Both of this connectors are usable with other LS throttle bodies. If you have an LS4 intake we make an intake adapter that allows larger LS throttle bodies to bolt to your intake manifold.
