After the posts on the Pure Stock drags I got inquiries about other stock classes people could run their musclecars in. The Catch-22 with these cars is they are extensively modified for maximum performance. If you entered your frame-off restored, numbers matching diamond in these races-even if you had a "King Kong" musclecar-you'd lose. The reason is the latitude the NHRA rulebook allows. For example-High-Performance Pontiac featured a "Super Stock" 1970 Ram Air IV Firebird Formula 400 that ran in the 10s. Now the RAIV was a 400 Pontiac V8 that had better breathing round-exhaust port heads that breathed way better than the standard "D" ports. These heads required special round-port exhaust manifolds. They also had an aluminum high-rise intake instead of the stock iron one. The cam had 308 / 320 Duration and with the 1.65:1 rockers, longer pushrods, special valvesprings and anti-pump-up lifters had .520 lift. A lot more than the .414 inch lift of the famous "068" or RAIII cam. This valvetrain would allow them to rev to 6,500 rpm. To beef up the bottom-end they used 4-bolt mains instead of 2, and forged pistons instead of cast, and a special 80 lb oil pump. They were only available with 3.90:1 or 4.33:1 gears. They'd run in the 13s bone-stock and a lot of magazines would put headers and slicks on them and drop into the 12s pretty easily. So how did this guy get his in the 10s without Nitrous? By strictly adhering to the rulebook! For example-engines are allowed to be within 15 cubic inches of their original size. Their ACTUAL size, not their advertised size. For example a 350 Pontiac is actually 354.5 cubic inches. So you could run a 370 inch motor and be within the rules. A 1970 and later SS396 Chevelle or Camaro engine is actually 402 cubic inches. So you could run a 417 inch motor and be legal-as opposed to 411 inches if the actual original size was 396 inches. In this case-a 400 Pontiac is actually 401 inches and change. So this guy runs a 3.79 inch stroke crank ( instead of the stock 3.75 ) which with a .040 overbore nets 416 cubes. He's running custom pistons which allow him to use 6.800 inch rods instead of the stock 6.625 size. The little extra stroke,15 extra cubes, and longer rods increase torque output substantially over stock. The heads have to be Iron-no aluminum aftermarket ones-but the combustion chamber volume has to be at least 62cc. This gives a compression ratio over 12:1-compared to the stock RAIV's 72cc chambers which give 10.5:1 with flat-top pistons. The cam has to be hydraulic-no solids or rollers-but there's no restrictions on lift or duration. The intake has to be stock-but they can be port-matched and extrude-honed, and you can run any size spacer under the carb as long the stock hood will close-no cutting up the hood for carb or air cleaner clearance. Many of these classes allow headers. Further you can run any axle ratio you want. This guy was running 5.14:1 gears!! And a TH400 with a 5,500 rpm converter and a trans-brake. Now do this math-do you think a 416 inch Poncho with 12:1 compression, longer 6.800 inch rods,a cam with over .600 lift, and 2 inch headers, a 5,500 rpm converter and 5.14 gears will run a tad faster than a stock one with 10.5:1 compression, stock rods,a .520 lift cam, iron exhaust manifolds and a stock 4-speed or TH400 and 3.90 or 4.33 gears??!! Like two or three seconds quicker!!! Another example is a guy who runs an L88 Corvette. Now the L88 was pretty hopped up in stock trim. 12:1 compression, a hot solid lifter cam, aluminum intake with an 830 cfm Holley 4-barrel. However the rulebook says he can run 13.5:1 compression, a .700 lift cam as opposed to the stock ( .560 ), 2.30 inch intake valves ( instead of the stock 2.19 ) and his double-pumper Holley is custom built to flow 1000 cfm. He's running a TH400 and 4.88:1 gears, and 2 1/4 inch headers and sidepipes. That's going to run a lot quicker than a bone-stock one with iron exhaust manifolds, and 3.36 or 3.70 or even 4.11 gears!!! I don't want to discourage anyone from racing their car-but don't think a concours-restored car can enter a "stock" class drag meet and be competitive. But if you wanted to build a "Clone"-your "LS6" Chevelle could run a 468 inch, 12.25:1 compression, a .600 lift solid cam, the 1969 and earlier L78 / L88 intake-( That's much taller than the flat LS6 one and worth 25 hp ) and any axle ratio from 3.31 to 6.14. Which would smoke a "real" stock LS6!! If you want to go that route, peruse the rulebook carefully, and use every trick you can. Mastermind
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