Fans of big-block Ford power are likely familiar with Jon Kaase and his engine-building outfit, which forged its reputation on winning Pro Stock engines. Pro drag racing programs are still a big part of the business at Kaase’s, but over the past several years, the company has been devoting some of its efforts toward hardware for those of us who don’t make a living on the quarter mile.
One of the biggest programs coming out of Kaase that isn’t devoted to pro racing is the Boss Nine, a recreation of the legendary Ford Boss 429 engine that was intended for use in NASCAR and homologated with a small batch of ’69 and ’70 Mustangs. Those cars are now worth well into six-figure territory, and the very rare parts and pieces for the Boss 429 engine are difficult to locate at any price. Even those hot rodders fortunate enough to piece together a set of Boss heads and associated valvetrain parts will be stymied by the need for a specific block – the standard 429/460 castings are not compatible with the Boss 429 heads.
But Kaase’s Boss Nine changes the game for enthusiasts, as brand-new aluminum Boss-style heads are available along with the signature rocker covers and all the other components required to finish an engine, particularly since the Boss Nine heads are designed to work with standard 385-series 429/460 blocks and head gaskets.
Jon Kaase introduced the new Boss Nine line of "shotgun" Ford-style heads and associated parts recently, and has now added a stack injection system for the engine that uses EFI and a hidden common plenum for streetability.
The latest addition to Kaase’s Boss Nine menu is a stack injection system, which gives the appearance of the classic mechanical injection unit from the golden era of drag racing, but with modern electronic controls to facilitate street driving, which traditional mechanical injection systems have never accommodated well. Though EFI has been merged with stack-type manifolds and throttle bodies before, the Kaase unit adds an interesting twist by concealing a common plenum beneath the intake, which helps to equalize pressures between the individual intake tracts and also provides a common vacuum source, yielding the correct signal for a MAP sensor and other vacuum-powered accessories.
The intake manifold conceals its common plenum on the bottom side, providing equalization between intake tracts and a common vacuum source.
In Kaase’s own testing, it was found that a 520-cu.in. Boss Nine engine running 9.8:1 compression and a hydraulic camshaft made an additional 30-lbs.ft. of torque with the stack injection arrangement as compared to a conventional carbureted induction system.
Kaase is currently offering all of the Boss Nine components as well as complete engines, built to suit the buyer’s desires. For more information, go to www.JonKaaseRacingEngines.com.