Inside The No. 1 Qualifier

This 0.75-inch-thick aluminum...        read full caption This 0.75-inch-thick aluminum spacer was provided by AllPontiac.com to be used on either side of the intake for proper fit on the raised port heads. This fitting allows the water to escape from a cooling chamber that was designed into the heads over the center intake ports (which has a hole in the intake flange to release the water into the spacer).

Here, Kaase removes one of...        read full caption Here, Kaase removes one of the Tigers for examination. These heads were originally designed by Don Johnston of DCI Motorsports and are now produced and sold through AllPontiac.com. They are made from T-356 aircraft-grade aluminum heat-treated to a T-6 rating. Each head weighs 40-45 pounds bare compared to 60 pounds for an iron Pontiac head. AllPontiac.com's IAII block has thick deck surfaces for improved rigidity and cylinder-head sealing. The exterior walls of the block are also thicker, and the head bolt bosses are tied into them for even more strength.

With the head off, we can...        read full caption With the head off, we can see the Cometic three-piece steel gasket that was sprayed with copper coating. It crushes to 0.041 inch, allowing the piston to sit 0.010 inch above the deck to get more quench area. ARP studs kept the heads from lifting with 12.4:1 compression through 200 dyno pulls. Kaase says he didn't need to O-ring the block and heads thanks to the Cometic gaskets. Here you can also see the siamesed cylinders of the IAII block and the beefy solid lifter galley with drilled oil return holes.

Top-End Highlights
The Tiger heads were ported to improve flow, and the chambers were welded and reshaped to reduce volume. Some of the features of the original chambers were retained--like the heart shape--which should promote swirl, but Kaase says his reasoning was to provide more quench area. The spark plug is biased toward exhaust valve--the hottest part of the chamber--for a quicker burn, but Kaase says he would have rather had it more toward the center of the bore to improve flame propagation.

Howe Racing Heads was involved with the head porting with JKRE. "We had specific cross-section dimensions that we wanted at certain points, like the pushrod and at the short turn," Kaase says. "We used molds to determine what was needed." The as-delivered intake port had a 310cc volume and measured 2.600x1.300 inches at the intake flange. Kaase says they aren't much bigger now. For comparison, a Ram Air IV intake port measures 2.200x1.100 at the flange.

In discussing the intake manifold mods, Kaase said, "We radiused the entry from the carb flange into each port, and we did lots of porting near the gasket area to match the intake to the heads and spacers. When all was said and done, no work under the carb flange would have probably only cost us about 10 hp or less. For all the work we did there, we didn't gain much."

'05 Jeg's Engine Masters Challenge Results For JKRE
Average horsepower and torque production of each engine as measured from 2,500 to 6,500 over three pulls is totaled and then added together to arrive at an overall score.