Ran across this interesting article where someone sat down and tried to figure out actual horsepower ratings of the muscle car era when factory under-rating was the norm. https://autowise.com/the-true-hp-of-the-10-most-powerful-classic-era-muscle-cars/ As an aside I had no idea at the time drag racing had such a powerful influence on the factory.
I have read that Denny states that the stated factory figures were accurate, but there's another number which is really critical to this issue - RPM. So many factory ratings were HP stated at a less than red line RPM. Now, you can say that's "accurate", and it "is" accurate "at that RPM". But, what's the maximum HP of the engine (and torque)? Often times, the max. HP is closer to the redline of the engine (further up the RPM scale). And, what just doesn't make sense, for example, is that the '70 Buick 455 engine specs state that the GS 455 was rated at 350 HP and adding the Stage 1 option (hotter cam, larger valves, lighter weight valvetrain, slightly higher compression ration (due to the increased sized of the valves in the CC), recurved distributer (ealier timing advance and earlier in RPMs) gets an additional 10HP to 360HP. Then ..... get this ... the same SR coded engine as the GS 455 (non Stage 1) engine put in the LeSabre/Electra/Riviera/Estate Wagon gets a 370HP rating @ 4600. Hmmmmm. What HP at 5000RPM? @5200? Then, all the Stage 1 parts do not account for more than 10HP (or not even if the SR engines are the same in the A-body or the B-bodies ... and they were the same)?
I would beg to differ. Huntington has been a respected name in the racing world for years. He even tested enough cars to develop a mathematical formula to predict quarter mile ETs and MPH, which can be found all over the internet. The other formulas are the Fox formula and the Hale formula, all based on Huntington's work.
X2 I always enjoy reading the January 1999 edition of MCR and their shootout feature article where they raced the big block Musclecars. Stage 1 (360 HP) ran identical trap speeds with the LS6 Chevelle SS (450 HP)
Unless a shootout article was written back in the day when you could still buy the cars new, I've always taken those with a grain of salt. Who's to say that decades later a 'stock' engine in these shootouts doesn't actually have a hotter cam in it (or some other hard to detect mod)? People do that kind of thing for bragging rights. I am aware that back it the day it also was not unheard of for the factory to 'tune' the car for one of these comparisons.
Physics doesn't lie. It doesn't lie about HP and it doesn't lie about Torque. As Denny Manner has said repeatedly, "People buy horseppower, but they drive torque." It's the torque which overcomes sitting still and moves the car. That is absolutely critical in a drag race. And, the Buick 455 is the torque King for a stock musclecar engine. Not just the 510 ft/lbs in total, but that all of that force is available at an incredibly low 2800 RPM - that's only marginally higher than the flash point of the torque converter. That torque is all in so early in the drag race, that some competing Brand Xer better have some HP on the big end to catch the Buick and some more to pull around it. (This is the real secret to the Buick 455's success)
I can read them as posted with my reading glasses. In any case, I e mailed the full sized scans to you
A convertible 4speed showed up the mighty 454 LS6, I think it’s fair to say if it had been a Turbo 400 automatic it would have been even better!
put your thumb and forefinger together and touch the screen then slowly spread them apart and the screen gets bigger.
Dennis told me that that 70 stage 1 engine, in production form, with blocked heat crossovers, corrected to the SAE standard at the time (60* dry air, 29.92 baro) produced 376HP at 5300 rpm. My actual dyno tests on stock engine confirm this, I have another on coming up here shortly. I have not seen that 510 torque number-- ever-- they have been more like 465-470, but my resto engines do not have the heat crossovers blocked, as this dramatically lengthens the on time of the well choke coil. Also, we correct to the modern SAE spec, of 72* dry air, with the same baro. Dennis believes that this is why we don't see that 510 number. What my resto engines do have is a much better valve job, and round cylinders- from using a torque plate. Back in the day, the threshold for risk insurance rates was 10 lbs curb weight per HP. Buick listed the curb weight to the Nhra just over 3600 lbs, so they rated the engine at 5000 rpm, where it did in fact make 360 HP. That all being said, the 455 Buick engine responds very well to just mild cam timing increases, and blueprinting. That engine may very well make 0ver 400 HP. I can tell you that a dead stock headed 70 Stage 1 455, with only modern cylinder prep, thinner rings, blueprinting, and a cam change/ compression bump to NHRA specs(13-1) makes 450 HP. JW
Probably 8-10 years ago MCR did a big buick issue. They interviewed denny manner. He fessed up the 70 stage 1 made 372 hp. About 15 pages later they featured a 70 GS stage 1. The author said something along the lines of the engine being famously underrated and actual HP was well over 400.. that one still makes me chuckle. You'd think the editor would catch that.
Hemmings mag does a very close to stock engine build every few months,..the last one was the L88 and it made an honest 580ish hp,..which wth wouldn't it haha 12to 1 comp solid cam rectangle port heads I would hope it could make 550+ ha
These arguments will Always be around. Always. Truth will never be defined. So many factors. So many answers. Funny thing to me now is how many of these bad a×× horsepower cars Ever even see the back barrels. We used to believe in the line... All the BS stops once you leave the line. Trust me we all ran plenty. All these trailer queens have no idea.
