Pushrod design is plagued with several problems. Firstly, pushrod engines suffer from a limited capacity to rev compared to overhead cam designs. This is due to their larger rotational mass, susceptibility to valve "float", and a tendency for the pushrods themselves to flex or snap at high rpm. The LS2's redline is at 6500rpm, compared to the 2JZ-GTE's higher 7200rpm redline. Secondly, pushrod engines have limited valve flexibility. Most pushrod engines only have two valves per cylinder (such as the LS2). Overhead cam engines, however, often use three, four or even five valves per cylinder to achieve greater efficiency and power. The 2JZ-GTE has four valves per cylinder, making a total of 24 valves for the engine. The LS2, with its two valves per cylinder, has a total of 16 valves for the engine.
In the form of twin sequential turbo chargers perhaps the biggest innovative feature of the 2JZ-GTE compared to the LS2 is its Telephone Number List use of forced induction. Due to the 2JZ-GTE having a low compression ratio, it allows turbo chargers to be run. A turbocharger is a device that compresses the air flowing into the engine. The advantage of compressing the air is that it lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. Turbo charging is perhaps the most efficient way to get power out of an engine - both small and large.
By using turbo chargers on smaller capacity engines Japan has been able to create extremely light, high-revving engines that are easily modified and have excellent fuel economy. Simple modifications on turbo cars allow for huge performance gains, especially in comparison to naturally aspirated engines. As an example, the 2JZ-GTE with an aftermarket exhaust, front mount intercooler and running a higher boost setting puts out significantly more power than the LS2. If one spends more money, the gains can be enormous. To extract power from a naturally aspirated engine is significantly more work.