We've all seen the stock factory ratings. I wonder how accurate they were. Most people assume the stage1 455 was way over 370hp. How much power did it really make? Was the 350 overrated? Has anyone ever built a stock 350 or 455 and dynoed the thing?? I don't buy the factory ratings on the 86/87 GNs either. They seem very underrated considering for the acceleration they have.
I guess I might as well raise the question now that I have a chance, does anyone know what a stock 1970 Buick 350 has?(I have a 2 barrel) Thanks! :Comp:
Wasn't the 70 stage 1 rated at 360? I thought the 70 wildcat 455 had 370. I wonder what the wildcat 455 makes.
Michael, Person asked what the actual numbers/hp was/is. Rated and actual are two different things. Denny stated 360 was for insurance purposes and was close to actual. I really don't think they cared at the time of a minor difference.
buick horsepower my first car was a 1970 buick skylark with a 350-2 barrel. they were rated at 260 horsepower.
Close... 376 at 5300... and also made 360 at 5000 rpm.. so they did not lie, just rated it at a specific rpm, but not at the peak. JW
was it a lie?? Buick rated the 70 Stg1 360@4600 ??? and the big car 455 370@4600 Are you guys trying to say that the STG1 made an extra 6 or 8 hp over the standard big car 455 and had to go to 5300 to do it? Sounds mighty fishy to me. Jim W., did you dyno a stock stg1 engine?
There is an awful lot of controversy when it comes to this subject. No question about it,the Stage 1 definately made some good HP numbers,but when it comes to actual ratings,that is Buick's best secret. If you were to take a stock 1970 GS Stage 1 and pit it against a stock 1970 Chevelle SS 454 LS-6,the Stage 1 would cook it. A lot of people automatically look at the HP numbers for the Chevelle which is at 450 HP, and thinking of what a Stage 1 is capable of doing to that Chevelle,who is the one that's lying? There's no question about it,Buick had one heck of a performance package and the Stage 1 was it.
I'm not sure about that either. Does anyone know what the actual rating was for the Hemi? My friend is really in to MOPAR and he said it makes more than 425 horsepower. We all know that Buick (Cadillac too I guess) is the torque king.
The ratings from GM were often often arbitrary and rounded to keep a 1 to 10 weight to power ratio relative to a hypothetcal 3600 pound car. Many intermediate cars were rounded to 360 hp--like the GTO, 442 etc. When you went to a bigger car like a Riv. there was plenty of weight to spare so they went to a 370hp rating. For the small valve engine in a 70 Riv for there was some fudging taking place as the engine was more like the 376 hp JW posted less a 10-15hp penalty for being the small valve etc. I do not recall the high performance (big valve ) version of the big Buicjk engine comming online until the 71 model year. As for the performance comparisons remember it is a function of the area defined under the torque/horsepower curve over the range of rpms pulled say in the quarter mile and not the peak horsepower during the run. All to often people just focus on comparing peak a rating from one make and model to the another's peak rating.
buick horsepower a stock 1970 buick skylark with a 350-4 barrel was rated at 280 horsepower. a 1970 gs 350 was rated at 315 horsepower and they were the same motors. the only difference was the gs350 had the ram air hood. we all know the ram air is not worth an additional 35 horsepower. this shows you cant get caught up in what they were rated at. carl is right, the 70 stage 1s would regularly whip the chevy ls6s, and the chevy was rated at 90 more horsepower than the stage1.
Ah, the good old days. The undercurrent here is that the insurance companies were idiots and took them at their word. I sort of wonder if that was really the case. Anybody know the difference in insurance between a Chevelle and a GS back at the time with the Chevelle rated at higher horsepower? Or the difference as mentioned above between a GS350 and a Skylark 350-4?
Insurance industry idiot now speaking.... :laugh: I have symbol pages back to 1959 in my agency and can look up the symbols, which is how the insurance industry rates automobiles. The symbols for 1970 and prior are just a jumble in my old book and not really defined, but if I use 1971 symbols, for which I have a full complete set of, I can make some sense of things. The higher the symbol, the higher the insurance costs, by the way. The 1971 Chevelle SS 454 was a symbol 5 with a "High Performance" subclass. The high performance subclass added an additional 50% to the insurance premium for that car. Quite a surcharge, especially considering the economic times. Oh, it didn't matter what 454 you bought, all had the same surcharge. The 1971 GS 455 Stage 1 was a symbol 4 with an "Intermediate Performance" subclass. The intermediate subclass added 20% to the premiums over a standard auto. More, to be sure, but not anything like what the Chevelle's were socked with premium wise. So to answer the question, the insurance industry did somewhat have the wool pulled over their eyes with the performance of the 455 Stage 1. Skylarks/GS's with 350's of any performance were all the same, symbol/cost wise. Skylarks/GS's were a symbol 4 (and had no performance surcharge). Electra's were a symbol 5, Cadillac's a symbol 6, just for example.
Great information Brad. You are amazing. I worked for Kemper back in mid to late 70s but was in the audit department tracking down fraudulent claims and such. Never was into the rating side of things. Thanks. So what you're saying is very interesting. The GSX was rated lower than a SS Chevelle. I'm just shaking my head in amazement. This is great stuff. The Corvettes must have been a 6 or higher. I bought a 65 Corvette in 1975 when I was 23 years old and was paying over $1100 per year insurance. At the time my salary was $9600 and it was killing me.
Yep, you could insure a Stage 1 GSX cheaper than a SS Chevelle. And by quite a bit, too. I guess the insurance industry was thinking the same as everybody else...no way a Buick can be that fast!
1970 SB code 350-4 was rated at 285hp and had 9:1 compression. The 1970 SP code had 10.25:1 compression and was rated at 315. It was the compression, not the ram air hood. I'm pretty sure the cams were different too.
First off; thanks for a lot of great info about the effects ratings. I know that horsepower means nothing if the car isn't fast in real life but I also know that friends and family will ask me how much juice I got under the hood when I show up in my "new" car. :3gears: I know it's hard to get an exact effects number as every car is different. I've bought a 1972 GS 455 that has some minor modifications done to it (see this thread for some background info). Based on this page the 70 GS 455 is rated at 350 HP and the 71 GS 455 at 315 HP. That's a 35 HP drop between 1970 and 1971. I know the measurements are done at different RPMs but can that alone contribute to the change or was the new engine (the 1971 engine was different from the 1970, right?) that much different? I've also read somewhere (here's one site that claims this) though that the 1971 GS was the fastest GS from 0 to 60 despite it having lower effect which, if it's true, only goes to prove that HP isn't everything. On this board I've read that a 70 GS 455 non-stage 1 engine is guesstimated to actually produce 360 HP, a 3% increase from the rated value. Can the same precentage be applied to the 1971 engine (in order to get the HP rating for my 1972 )? If so it would produce an actual 325 HP (x 0.8 = 260 HP SAE Net). Does that seem like a reasonable number or have I managed to trip over all the conversions and estimates? :grin:
The 71 was derated because the compression was lowered from a rated 10,25 to 1 in 1970 to a rated 8.5 to 1 in 1971. As a rule of thumb that will lower the hp 5-6%. (The hp to compression function is not a linear curve.) I do not think there is any debate but that the fastest Buick out of the showroom was a 70 gs stage 1. FFor this reason it was listed number 3 fastest behind the 427 Vette and the 427 Cobra ehn the muscle car era times were compiled by Car Review in Nov 1984. There can be no honest debate about the fact that the 70 year model had the highest output engine. Except for a lower hp engine and cosmetics the 70 and 71 GS cars were the same. From the site you linked: 1970 GS Performance: GS455 Stage 1 - 455/360: 0-60 in 6.2 sec, 1971 GS Performance: 455/315: 0-60 in 6.9 sec,
