In this business there are occasionally projects that'll really blow you away. Last month we introduced you to The Hunter, a new engine that Hye Tech Performance assembled using a whole lot of off-the-shelf parts from Jeg's mail order. It's a 496-cid stroker Rat built for one simple purpose: to take no prisoners on the boulevard. We also told you that this was no ordinary pump-gas big-block either. Unlike so many sleeper build-ups of the past, its design was made to get attention as it rolled down the street; which it would have little trouble doing judging from the way it performed on the dyno.
Pump-Gas PowerEven though this engine emits an exhaust tone that's reminiscent of the high compression big-blocks built long ago, its pump-gas friendly 10.25:1 compression (mistakenly reported as 11:1 in last month's story) means that this beast can be filled up anywhere and for very little cash. That leaves plenty of money behind for new back rubber because this thing makes enough torque to fry any set of meats. How do 700 peak horsepower and over 640 ft-lb of torque, all below 6,500 rpm grab you? Like a giant python, this motor will squeeze every last bit of performance out of your car and anyone else you pull up against. In a 3,200-pound car with around a 3,500-rpm stall converter and some sticky tires, this engine would easily dip into the 9s and you could still drive it home.
Motor MaintenanceAlthough this is a pump-gas street bruiser, its race-inspired components will still require periodic maintenance to live a long healthy life. With a solid roller cam as big as this one is, you'd want to check valve lash about once a month if it's driven regularly. Also, keep an eye on the spark plugs, looking out for any signs of detonation (black spotting on the porcelain) because some gas stations have been known to put low-octane gas in their high-octane tanks and scam a few bucks. It'd be wise to carry a can of octane booster in the trunk, or better yet, add one every time you fill up, just to be safe. It's cheap insurance against a massive failure. Also, the Weiand (pronounced "Why-And") Team G intake manifold is very tall at over 7 3/8-inches. It might not clear any stock musclecar hoods or most factory cowl-induction hoods either. So, if you're planning to build an engine like this one, be prepared to buy a tall, fiberglass cowl-induction hood because the further you can keep the hood above the carb, the better you'll be able to breathe.
The Hunter's First StrikeNote: Last month we incorrectly listed The Hunter's compression at 11:1. Then engine builder Hye Tech Performance told us it actually turned out to be a more pump-gas friendly 10.25:1. Even though our original plan was for around 11:1, we felt that with aluminum heads and a large camshaft, 11:1 would work. However, in keeping with our plan to use off-the-shelf parts, the only SRP Pistons available, in conjunction with the 119cc chamber size, gave us either 10.25:1 or 13:1.
Test ResultsWhen we bolted The Hunter onto Westech's Superflow 901 engine dynamometer we were expecting to see an easy 700 hp. But, expectations can easily go awry in dyno testing and the engine immediately had trouble cranking out just 600 hp. After a very troubling morning, we figured out that the carb we had been using wasn't metering fuel properly. With no time left to diagnose the problem further, Westech loaned us one of their Holley 9375 Dominators and power immediately began looking promising. Then we swapped rocker arms from a 1.7 to 1.8 ratio and found an incredible amount of extra power, indicating that this motor really wanted more camshaft. But the street aspect of it denied us the chance to install a bigger stick, so we stuck with the original cam and 1.8:1 rockers. Lastly, we tried a few different carb spacers, the best of which was a 2-inch tall aluminum HVH Super Sucker, when we finally crested the 700hp mark. This reinforced the notion that making 700 normally aspirated horsepower on pump gas is nothing to take lightly, especially with under 500 ci. But the right combination and a heck of a lot of hard work can really pay off.
Rocker Arm SwapThis chart shows the extra power we found after swapping to 1.8:1 ratio COMP Cams stainless roller rockers. This proves that The Hunter would like a cam with more lift and faster lobes. At 6,200 rpm, the 1.8 rockers added 38 hp and overall average power increased by 26 hp. While this is not typical of increases usually found with just a ratio swap, it proves that whatever you're dynoing there's always power to be found.
The Hunter's Build Sheet
Note: there were a few parts changes so throw out last month's parts list and keep this one if you want to duplicate this engine
Jeg's Heads By The NumbersThe Jeg's J-series BBC aluminum cylinder heads used on this engine were not right out of the box. We asked the guys at Hye Tech to lightly polish the exhaust ports and gasket match the intake side, which is very common work for an engine of this type. Here are the flow numbers Westech measured after porting:
All figures are at 28-inches depression on a 4.600 bore plate.
PN 555-51455 Rect port(119cc chamber, 310cc intake)Valve dia: 2.25 1.88