Scott Main and team MPG Heads brought a 404-inch, Cleveland-headed, small-block Ford to do battle against the rest of the small-block class at the 2016 AMSOIL Engine Masters Challenge presented by HOT ROD. Scott likes the small-block Ford platform because of its great cylinder head design and knew he could whip up a stout competitor with some hardcore time on the dyno and by selecting the proper parts. Scott told us that Cylinder Head Innovations (CHI) is always happy to work with engine builders in developing performance packages, and they, “seemed to be the top of the food chain for that RPM range.” In other words, right where a 400-inch street engine needs to be making power. So how does CHI, an Australian company, wind up making one of the top Ford cylinder heads? While Windsor took over in the States, Australian production of the Cleveland continued on until the early 1980s, and remaining stocks of the engine were used in new trucks until 1985. As Scott said, “In Australia they’re all about Fords and Clevelands are huge down there.”
MPG heads tried several varieties of CHI heads and found the one the worked best for the competition parameters, developing a port shape and five-axis CNC-porting both the heads and intake. The resulting ports offer both high flow and high efficiency, delivering flow at modest lift levels. Scott grinds his own cams using 8620 billet steel blanks, so he had plenty of opportunity to try different duration and lift, but found that increasing lift from his chosen .750-inch lift didn’t add significant power at the cost of valve spring longevity.
The heads are so efficient didn’t need much lift to get the job done.” – Scott Main on the CNC-ported CHI heads
Come competition day, the hot-rodded Ford averaged 578.8 lb-ft and 606.3 horsepower between 3,500 and 7,500rpm, with a peak power of 756hp, earning the team the small-block class win. Scott was pleased with the peak number, as his testing was done in his Colorado shop. The 6,000-foot elevation isn’t conducive to big numbers, “I was surprised that at the lower altitude the engine kept making power.” Even more impressive is that there are no secrets about the engine, no exotic parts, and no trick epoxied intake runners. Here’s how Scott Main and Jay Kidwell built a streetable, repeatable recipe.
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