69 Z28 302 Crossram Pg. 1
1969 Z28 302 Crossram Project:Taming a Wild Mouse
In the late 1960's and early 1970's, horsepower ruled the streets. Every auto maker from AMC to Pontiac had a variety of performance options available for those whom spirited driving was a priority.
Chevrolet was certainly in the game as well, turning loose on the streets one of the wildest animals ever to roam the roads--the 1969 Z28 Camaro with its high-winding 302 cubic inch small block screamer. Despite its diminutive displacement, the little 302 "mouse motor" quickly became a force to be reckoned with.
The 302's main advantage on the street was actually its lack of low-end torque, and its ability to make strong power at an rpm level where most other engines were starting to sign off. While the torque-laden big block powered rides were often fighting for traction, the high-winding little 302 could quickly put a considerable gap between itself and its competition, and by the time 4th gear came around it was all over but the crying.
Given the fact that the 302 was developed mainly for the race track, one would expect such an engine to be a high-rpm screamer. For those who considered "too much" to be "just right", GM also offered an over-the-counter optional crossram intake manifold with a pair of 585 cfm Holley carburetors to replace the factory dual plane high-rise manifold and 780 cfm Holley carburetor. Putting aside the potential for increased power output, the crossram had one other thing going for it as well--a rather stunning visual impact. Even today, 40 years after its introduction, when the hood comes up on a crossram-equipped car, a crowd is quick to gather. An obvious perk for the street crowd.
In practical application, the crossram intake system added notable power in the upper rpm ranges, which was exactly what was needed on the race track. However, with its huge common plenum design, the crossram intake made the 302's already-lacking low-end torque situation even worse. Not a problem on the track where the engines seldom saw the low side of 5000 rpm, but definitely not ideal for street use.
Even in stock form, the 302's lack of low-end torque often made for somewhat labored street manners under less spirited driving conditions. A wide-ratio 4-speed transmission was a welcome addition behind many 302's, as were rear end gears well into the 4-series range and beyond. Excellent for racing, not-so-hot for daily commuting. Road trips? Only for the bravest of the brave. In the simplest of terms, a 302 needed to rev to do its thing.
Even so, this didn't deter people from running a crossram intake system on the street in the never-ending quest for more power. The results were what one should expect...even less low-end power, making daily driving even more laborious.
Despite these issues, there are still many die-hard enthusiasts who are willing to take on the challenge of running a crossram system on the street. One such enthusiast is Indiana resident Gary Westveer.
In November 2006, Gary contacted me about building a 302 crossram engine for his rotisserie-restored 1969 Z28 Camaro project. Gary wanted a strong running engine that remained true to its racing heritage, but it also needed to be docile enough to take on a small road trip should the desire arise. Not an easy task given the circumstances, but after discussing several options with Gary, I agreed to take on the project.
My job was clear;
I had to tame the wild mouse.
Follow along with the build-up and see the final results as my work is put to the test on the dyno.