Manifold design can make or break an engine, but it’s often a compromise between what design will offer the ultimate in performance for a given application, and what design will be the best fitment on the vehicle that houses the application in question. Many different designs have been tried over the years by many different fabricators, and lately we’ve seen twin-throttle-body cross-ram-style manifolds making a resurgence. 

Nelson Racing Engines has developed a new design called the X-Ram, and shows its capabilities in this video when pitted against another more conventional manifold back-to-back on the same engine. The engine in question is a 496 cubic inch LS based piece, and with the X-Ram manifold on top it cranks out 690 horsepower and 696 foot-pounds of torque with 600-plus foot-pounds available from 2,900-5,900 RPM. The engine uses a small hydraulic roller custom camshaft and a number of high-tech pieces to achieve the power level.

According to Nelson, the engine with this manifold is run on pump gas and makes more torque than a standard GM 572 crate big-block, yet fits in the small-block footprint. 

The engine is run back-to-back with the X-Ram against another manifold which doesn’t match up in terms of ultimate power and torque, nor average power and torque for that matter. The X-Ram makes substantially more power and torque across the board, showing that manifold design is critical for optimizing a particular engine – you need to have enough airflow capability in the manifold to support the level of power the engine is capable of producing. 

As the X-Ram uses a pair of 90mm throttle bodies versus the single throttle body used on the other designs, and this back-to-back test highlights the differences in manifold design and power production, especially on a larger engine.

While the 496 is not a monster in terms of displacement, it is a very, very large small-block and needs big-block-style airflow in order to make maximum power.

The sound the engine makes with the dual throttle bodies and X-Ram on top is simply insane. Headphones help…