NHRA Stock Class Racing Explained 

Me too gary, I like to get to the track on friday and take in all the stock and super stock. The best is a event that has class runoff like Indy SS.

That’s first thing came to mind lol absolutely

Not really man I do asphalt oval track racing and run in a outlaw stock class and my motor is a stock block 350 and steal heads and a 800 CFM carb with stock intake making 585 hp to rear wheels and if I put that in one of these cars and made it more stock it would do wheelies cuse of the suspension and weight transfer they don't have stock suspension and they put it on scales tognet the rear weight percentage right,

The Suspension on these cars are Stock . Aftermarket shock and Spring are allowed. Only a bolt on traction device allowed. Also limited to a 9 inch tire . So it's incorrect to say the Suspension is not stock. You can't modify the original type of Suspension the car came with . Example , If the car came with a leaf spring Suspension you have to run a leaf spring . Yes weight transfer. Spring rates and shock adjustment are the trick to making our cars work . Mind you most these cars weight 3k plus pounds . Rear gear and Transmission play a huge part in getting these cars to 60ft as well . Have a good day 👍

It's been tried. Yes, the aftermarket manifold makes more power. An iron intake from a Chevy 327/250, picks up a 283/220 by about a .10! Unless you have an engine that had an Edelbrock manifold as OEM, such as a 69 440 Six Pack. The wrong year intake will get you DQ'd. A 1" carb spacer will pick up my 305 by .075, ET. We are allowed 2 stock gaskets only. I know Doug. He is one of the sharpest racers out there.

My 79 mustang came with a 302 2 bbl rated at 140hp. Since this combo has been thrashed on a bit, nhra added a few hp here and there according to how far under the index it ran. Now it is rated at 134hp. I run U/SA (U stock auto) and in U, the hp to weight is 20:1 so by adding 4hp, that means I have to add 20lb's per hp or 80lb's to my car to be legal. Where it was 140x20=2800 lb's minimum, now it is 2880lb's. that's about 2/10's it slows me down. in a heads up race with another U/SA that means I am at a disadvantage by 2/10's now. Where do you find the HP ratings? NHRA posts them all as well as changes up (or down). Also note that ford had a 302 with a 2bbl VV or Variable Venturi carb. Here's my engine hp numbers as well as others available for a 79 mustang and their respected ratings. Note too S is for Stock and SS is for SuperStock hp ratings. Cu.in 200 140 171 171 140T 302S 302S 302SS 302S 302SS Ford hp 85hp 88hp 100hp 109hp 120hp 140hp 140hp 140hp 143hp 143hp and the "factored" hp by nhra NHRA hp 140 114 130 120 150 143 147 143 143 143 Hopefully this clears it up a bit. Almost all engines have been "refactored" by nhra so a 89 mustang which came from the factory at 225hp has been decreased to 215hp due to it being slow as factory rated. an 08 mustang with a 330 cu in engine was factory rated at 425hp but due to it getting hit with hp, it is now rated by nhra at 498 with manual and 536hp with an auto.

I race circle track and that what happened with us. We had to run a sealed crate motor. And believe it or not, it's a trickle effect and ruins the racing for the racers and fans.

Absolutely not!! That takes away the main thing about class racing, innovation! Some go to a junkyard and get 10 sets of heads to get the best flowing factory head (with the exact same part numbers) so they can win heads up races. What you're proposing is make generic cars like the iroc series and see who the "best driver" is. That is NOT stock!!! When you see a 283 4 bbl wagon with a 4 spd stand on the back bumper with stock carb/intake/heads/cam lift/etc then you can get an appreciation for how dedicated and how much testing and work goes into a stocker!

It's almost impossible to find some casting numbers now. As long as the valve and combustion chamber sizes as well as port volumes match the stock heads, aluminum heads are the great equalizer.

@@r.d.riddle2068 Yeah that’s a good point, just disappointing to see aftermarket aluminum heads in stock class, there should at least be iron alternatives…

@@shitbox82 try to find 50-60-year-old heads that are not butchered. I had a hard time finding good heads from the 80's. The stroke has to be within .015". No HP here.

@@JohnW1711stock Oh yeah I don’t doubt that for a second, I’m just saying I wish someone offered a few iron replacement castings for some of the more popular combinations, but it is what it is that’s just my opinion, I’ve always been a huge stock fan and always will.

@@shitbox82 I agree. Nobody will duplicate old iron heads. There is a HP penalty for aluminum heads, from the NHRA list, for most engines, in Stock and Super Stock. The 396/375 is plus10 HP. with Bowtie heads.

Most of the old heads, remember this stuff is over 50 year old, have been used up. The aluminum heads had to be the same specs. of the stock heads.