As "Harry Hogge" said..."There's nothing stock about a stock car..."

I've had a lot of people ask me how participants of the Pure Stock Drags and other similar events run such blistering times-often a full second or more quicker than any road tests from magazines back in the day. There are many reasons for this and I'll explain them. In the Tom Cruise racing blockbuster "Days of Thunder"-grizzled crew chief "Harry Hogge"-brilliantly played by Robert Duvall-said-"There's nothing stock about a stock car." Truer words were never spoken. # 1. The Rules. Often the rules for these events are based on the NHRA's Stock Class or Super Stock class rules. These guidelines give builders quite a bit of latitude. I'll use a couple of recent champions to illustrate. One was a Ram Air IV Firebird. The rulebook says that engines have to be within 15 cubic inches of original. Pontiac 400s are actually 401 cubic inches. So he can build an engine 416 cubes and still be legal. 400 Pontiacs have a 4.12 inch bore and a 3.75 inch stroke, and connecting rods 6.675 inches in length. He achieved 416 inches by boring the block .030 over and by using a custom 3.79 inch stroke crank. He also used 6.800 inch connecting rods and custom pistons. This may sound like small "technicalities" but experienced engine builders will tell you that a longer stroke and longer connecting rods build a lot of torque all through the range. This why small-block Chevy racers in NASCAR have used 6 inch rods for years. ( Stock length is 5.7 ). So already-with a little machine work on the bottom end this car has a substantial advantage. All other things being equal-do you think an engine with 15 extra cubes and longer rods is going to run harder than a bone-stock one?  The rulebook say the cam has to be the "Original Type". What this means is if the car had a hydraulic cam from the factory then you have to run a hydraulic cam-no solid lifters. If the car had a solid-lifter cam from the factory, you can't run a roller. The loophole is their are no limits on duration and lift. An RAIV from the factory has a cam with 308 / 320 advertised duration ( 231 / 240 @.050 ) and .470 lift with 1.5:1 rockers. ( .520 with 1.65:1 rockers.) This guy was running a cam with 253 duration ( @.050 ) and .575 lift with 1.5 rockers. Think an extra .105 in lift will make some extra power? Especially on the top-end?  The rulebook says that cylinder heads have to be the original type. Meaning if the car had iron heads, you can't run aluminum ones. For Pontiacs it says the minimum combustion chamber volume allowed is 62cc. 1969-70 RAIVs had 10.75:1 compression with 72cc combustion chambers. By milling the heads to get to 62cc-he effectively raised compression to roughly  12:1. The intake manifold has to be the original type. RAIV's had an aluminum intake-so he can run a factory RAIV / 455 HO piece or run a repro RAIV intake from AMEs or NPD or other Pontiac resto houses. However-the intakes can be port-matched, and the only limitation is the stock hood has to close-no scoops or bulges allowed. That means he can use a 1" or 2" inch spacer under the carb as long as the air cleaner clears the hood. The carb has to be the original type-a Quadrajet-but he's running a custom one that flows nearly 1000 cfm ( stock is 750 cfm ) and has a larger .149 needle and seat so he can run extra fuel pressure-9 psi. ( Stock is 5-6 psi ). He's running a 4,300 rpm torque converter and 5.14:1 gears. Now do you see the difference? Of how this car, with 15 extra cubes,a much hotter cam, higher compression ratio, a ported intake, a larger carb,extra fuel pressure, a high-stall converter and 5.14:1 gears can run low 11s while a stocker with 3.90:1 gears can only run in the 13s?  The other example is an L88 Corvette. This one also runs low 11s. Now L88s were pretty radical from the factory-they had 12:1 compression, a hot solid-lifter cam and an 830cfm Holley on an aluminum intake. However- the rules allow up to 13.5:1 compression for L88 spec cars!!  Again-the cam has to be a flat-tappet solid lifter design-but there's no limit on lift or duration. The Chevrolet "off-road" cam has something like 258 duration ( @.050 ) and over .600 lift! He's got a port-matched intake, and the custom Holley carb flows over 950 cfm. He's also running a 4,500 rpm converter and 4.88:1 gears. That's how he rips off consistent 11.40s while the stocker tested by Hot Rod with a TH400 and 3.36:1 gears back in the day ran mid 13s. ( Another L88 / 4-speed 'Vette test car with 4.56:1 gears did run in the 12s; but that's still a far cry from 11.40s ). Are these guys cheating?  No-they are within the rules to the letter. Are their cars "Pure Stock?"  Hell no!!!  # 2. The second factor is tuning and testing. These guys spend umpteen hours tuning and testing. The grand champion a few years ago was a 428CJ Mustang. Musclecar Review had an interview with him. He had changed cams a lot and found that Lunati's version of the factory CJ cam gave him much more power than the stock Ford cam or the Crane "Blueprint" series or the Comp Cams version, epecially above 5,000 rpm. That's costly and time-consuming, but the edge it gave him was undeniable. His intake and exhaust manifolds were port-matched and extrude-honed for maximum flow. He re-jetted the carb for altitude and specific conditions at each track he raced on. He had changed leaf springs many times- and found that a set originally off a 390 Cougar gave him the best launch. He played with shift points and found that the car ran hardest if he shifted the C6 manually at 6,200 rpm ( 1-2 ) and 6,500 rpm ( 2-3 ). All this work will definitely give him an edge over another 428 Mustang or LS6 Chevelle or Six-Pack Road Runner or whatever-who just goes to the event, pulls to the line and punches it!!!  So you can go that fast-if you want to invest the time and money. But don't feel bad if your lovingly restored stocker can't come close to these "Ringers".  Mastermind