[70RAlll]

Originally Posted by Jim Rotella

These Pure Stock cars are not bone showroom stock. They are allowed some minor modifications, but nothing really radical. If you look at the article closely, you'll see that Mark's bottom end was balanced, the compression ratio was increased to 9.63:1, the carb was rejetted, the distributor was recurved, and the exhaust was upgraded with a 2.5" mandrel bent Pypes system and an X pipe. These engines really respond to those legal PS tweaks. Just look at Paul Glasco's '70 Knafel Magnum 400 clone in that same article. With similiar modifications, it ran a corrected best time of 12.29 at 112.80. There are several Ram Air IV and SD455 cars running mid-to-high 12 seconds in these PS races. It's really amazing what they are doing with these cars.

Guys, I am sure everyone will start screaming at me. But I am sceptical at heart. A 71 HO engine just doesn't run low 12's in stock form with re jetting and distributor re curving. These cars never were Quarter mile cars. Pontiac 455's torque/HP curves fall like a rock past 4500 RPM.They were always red light to red light monsters,still are!! But the stock valve train just doesn't suite high rpm full throttle service.Have any of you guys ever gone over 100mph in one of these cars with a 3.73 rear?? something like 4500 rom or more,brutal. I would be a believer if they did a random tear down ,or at least removal of valve covers after a race. It is so easy to hide internal modifications now a days. And like I said, these engines weren't designed to run the high RPM"s that a 12.40 QM would indicate.Ask any engine builder,like the guys at Butler, if they think a stock(which essentially that what this engine is-minus a dist. and carb tune) 71 455 could run a TA into the low 12's.They own their local track and I know without a doubt their answer is yes with internal modifications to the heads and valve train, but no using stock heads with stock ,non adjustable valve train.And guys ..think about this. The technology of rejetting a Quadrajet and re curving a distributor have been around since these cars were new. I don't even thinkthe 70 hemi 'cuda's ran low 12's in near stock form.They were the absolute King of the QM in their day. If TA's in stock form could do this, we would have seen articles proclaiming these cars the new king of the track.
And guys, I am sure I will get a bunch of trash talk back at me for suggesting this. But I just don't get it. I am not super expert engine builder, but I do build all of my own engines here at my shop ,by myself. SO I know a bit about the chacteristics of these engines. Granted I have NEVER ran a QM in one of these, so I could be dead wrong here. Just doesn't make sense to me that simple jetting and re curving could slice almost a full second off generally accepted stock times. Heck the Motion Camaros were only guaranteed to run 13's...we are supposed to believe that near stock TA's are running 12.40's without internal modifications?? I am still skptical.. Please someone help me see what I am missing. I am not too much of a smarta$$ that I can not accept when I am wrong.To the contrary...I would love for someone to show me where i am wrong.

[njsteve]

Not nickpicking here but the Motion Camaros were gauranteed to run an 11 second quarter mile with one of their drivers behind the wheel or you got your money back, NOT 13 seconds.

[70RAlll]

Originally Posted by njsteve

Not nickpicking here but the Motion Camaros were gauranteed to run an 11 second quarter mile with one of their drivers behind the wheel or you got your money back, NOT 13 seconds.

shows how much I know about Camaros. I had asked a guy who restores Yenkos, he told me he thought it was 13 seconds. I sort of took his word, 2 time muscle Car of teh year recieptient.. anyway, I could have heard it wrong.. but still, someone help me understand how our cars run 12.XX sec. QM's in near stock form.. ??

[keith k]

Originally Posted by 70RAlll

shows how much I know about Camaros. I had asked a guy who restores Yenkos, he told me he thought it was 13 seconds. I sort of took his word, 2 time muscle Car of teh year recieptient.. anyway, I could have heard it wrong.. but still, someone help me understand how our cars run 12.XX sec. QM's in near stock form.. ??

Bill, the latest issues of HPP have fairly detailed stories on how they're doing it. I do believe it's possible for these cars to run these times with the attention to detail, expertise, and tricks that have been lavished on them.

I think you are correct in how these cars ran when they were TRULY new/original/stock/factory. The Pure Stock series does allow some deviations from stock, that in conjunction with some of the other set up allowances, and drivers who are pretty darn good, explain the times they get.

I hope to make it out to their event this year to see the cars in the flesh.

[74 SD455 Formula]

Also if you read the whole article you'll see that they have special grind cam shaft's.The lift and duration are the same,but the difference is in the lobe speration.What Dan Jensen does with his motor's make's sence if you talk to any knowledgeable Pontiac engine builder.

[threefidee]

The first article of this series (last month's issue) states "remember not to get caught up in the semantics of the words Pure Stock." They used the word "Pure" when this all got started to weed out modified cars and that most of the cars that participate at the event are not the literal definition of "pure stock". They started this informally back in the early '90's with a small group of people. From what Mark tells me is that many of these people ran their cars in Stock NHRA and the only things they had to do was put the right tires back on them and put the manifolds back on (I am probably leaving something out here) and they had some fun. Since these guys for the most part were using NHRA specs at the very beginning they adopted the the NHRA blueprint specs to use for building engines for everyone. It was never intended to be a "Virgin Stock Class" so one has to remember not to take the word "Pure" literally as I am glad they do try to explain this in the article. Whether you agree or not this is the way they do it. I remember when I was first introduced to the Pure Stock Muscle Drag Racing and saw my first event I remember telling my dad that this can not be right as these cars are going faster than what I had always read in magazine articles. Then it was explained to me about what I have mentioned above and made sense. Keep in mind that even though the NHRA can give you more compression to use, ect... the main reason these cars are faster are these. The reproduction tires are much better than they were back then and with that combined with the track being "glued" they hook like drag slicks. The other main reason is they are allowed to use a much better exhaust system than what left the factory. 2 1/2 inch mandrel bent systems with "X" pipes really wake many of these cars up. Ask Mark how much his Judge improved by just switching exhausts from the factory show to the 2 1/2 inch system. It will amaze you.

Thanks for listening,

Jody

[Jim Rotella]

There's definetly more to it than recurving and rejetting. To get these times, these engines are balanced and blueprinted, something that is rarely done at the factory. They are allowed a boost in compression and these builders are also aided by the use of a dyno to supertune their engines. As Jody has posted earlier, the 2 1/2" mandrel bent exhaust system with an X pipe flows much better than the old 2 1/4' factory bent system. Just take a look at a '71-'72 Trans Am with stock 455 HO 2 1/4" head pipes as they come out of the exhaust manifolds. The first 90 degree bend is crushed down to probably 1 7/8", and as you follow the system back, there are similar bends going into the single crossflow muffler. This has always been a horsepower-robbing system.

I'm sure everyone has their own little tricks, but with such a large number of cars turning 12's, are we to assume that everyone is cheating? We are seeing RA II's, RA IV's, 455 HO's, and SD 455's getting into the mid-12's, not to mention all the others makes that are turning these times. I say give these guys credit for a job well done.