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I spoke with a guy at a machine shop and he told me that the most horse power you can get out of a street motor is about the same amount of cubic inches your motor has, because of street gas octane you can only run 10:1 compression. I am building a 377(a downstroked 400) and I heard that they can have 450-500hp. I was wondering if what he told me was entirely true?
 

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No, it was almost entirely wrong.

More than one horsepower/cubic inch is quite attainable. Many factory high performance engines do much better than 0ne hp/cubic inch. In addition, particularly with aluminum heads, more than 10:1 compression is also quite feasible.

Look at some of the signatures of people in these forums to see what they are getting for horsepower and using for compression ratios.
 

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I would say it's about 70% correct--it was designed to get you in the ball park with a good estimate, I have a true 535hp 388ci--Desk Top Dyno claimed my set-up is mking 610hp.
 

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My 11.2/1 383 stroker runs on 92 all day long in 95 degree weather in stop and go traffic. Although the aluminum vortec heads,6" rods,and big cam help alot. I even tried 89 once and it worked,although I didnt take over 4000. Im amazed, but it works. If I did it again I would put the dished pistons for 9.8/1, this high compression scares me.
 

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I have a great 357cid (0.040 over) with 11:00 compression using Edelbrock Performer RPM heads and MSD 6AL ignition. NEVER a problem running on 92 octane and this little engine is one that will do.
 

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Ill run it for ya cruzer, Whacha got

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67 prostreet BB Camaro
80 z28 Camaro 355ci
71 BB SS Chevelle (clone)
2002 35th anniv SS Z28 conv.
 

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I agree- desktop dyno's power curves, peak hp rpm, etc are pretty decent... but the hp # is off-- my 358 just came off the dyno in June after a freshenning, I gave desktop dyno the head flow #'s and everything, it said 570+hp... My best pull on a standard 750 double pumper was 517.8hp; going to a reworked 750HP got 530hp; adding the Moroso vacuum pump got 542hp. This dyno and builder seems pretty honest... his dyno is a good 10-14% under the other engine builders around here... but does line up with one independant dyno shop, and Moroso's slide chart for speed, weight, and hp for drag cars. (Which Moroso says is crank shaft hp, so I guess they are right). -Dan
 

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Why are you destroking the motor? Morecubic inches are better on the street, IMO. The more CID, the more torque. You dont need to rev it for a street application, so i see no need to destroke it.
 

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I can't speak for all the 302 Z28 guys, but my stock 11:1 302 with iron heads runs fine on the 92-94 pump stuff. It seems that one of the major factors for running high compression ratios, is to run a very long duration cam (like the 30-30!)....
matt
 

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Well, as a wise dragracer once told me, horsepower wins drag races, torque wins tractor pulls.

If you can afford real good heads, like a set of raised runner 23 degrees, or even better 18 degree left over winston cup stuff... a 377 is near ideal--- the big bore unshrouds the valves for more flow, and the 377 combo is a good intermediate to still have plenty of torque, great rod ratio, and be able to spin 7500-8000 rpm, which is where those high dollar heads can make some incredible power.

The more rpm's you can spin, the more horsepower you can make... remember, horsepower is only calculated off the torque, and while big torque can get you out of the hole, once your past the first 100-200 feet, it's all horsepower. -Dan
 

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anyone ever have anyone tell you that 400 horsepower is the most that is "street legal"? i hear that from time to time... or how about when someone asks how much power you have, and you say maybe 400 on a good day, and they ask where you get the 110 octane leaded gas you need to run it?
thought i'd ask, because it is KINDA related to the original posting...

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
 

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Your machinist seems to be a realist. A lot of guys think that they have a 450 small block that only have a 350 HP small block.

Desktop Dyno says my 383 has 463 HP at the flywheel. I have run 11.9's with the car. When I put it on a chassis dyno it pulled only 317 HP at the rear wheels. Welcome to reality!

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68 Camaro with 383 small block. ET - 11.9's at 112 mph and never trailered.

The combo:

10.3:1 KB pistons, Eagle cast crank, 5.7" SIR rods.
Trick Flow 23* heads ported 2.055 intake, 1.6 exhaust.
Comp Cams 282s mechanical cam with 1.6 rockers.
Victor Jr intake and Holley O-3310 carb.
1-3/4" Hedman Headers, full length Flowmaster exhaust.
TH350 trans, 3000 stall, 3.55 gear.
CE subframe connectors, drag shocks, SSM lift bars.
 

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"Well, as a wise dragracer once told me, horsepower wins drag races, torque wins tractor pulls."

Don't believe everything you hear...

Take a 4-banger that makes 300HP peak and a 350 that makes the same. (You know the torque curves will be different...)
Now, put them in the same exact car, say, a 3200 pounder. Who will win in the 1/4? And why?

That "wise old dragracer" was a little too simple-minded... there are too many factors involved when setting up a car for straight-line to generalize like that.

Ever hear any "wise old dragracers" say that the race is won in the first 60 feet?
 

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Actually, they would show the same mph at the top end... It physics, or as we call it - God's dyno.

Yes, torque will help you e.t. if you have the traction to use it... but the point is, when looking at a 377 vs a 400, if you can set the 377 up with the right type of heads, it can make more horspower.
 

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since when does MPH win a drag race.
ask Ed bigley if torque wins drag races, he's been winning quite a few with Torque power!
the reason the wise old drag racer might have thought that was becuase he couldnt get a torquey car to hook up, therefore leading to the belief that torque doesnt win races.
 

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I have postewd this before about the guy that had the 454 B&S'ed Ford side-oiler powered Cobra.

He ran it with a passenger to even out the weight.

It either bogged, spun/smoked out off the line or when feathered just right kinda rose up on all four's and took off like a stripped a--ed ape, hazing the tires all the way down the strip. To the tune of 11's, don't remember the exact number!!!

You can have t and hp if your car is set up for it AND you can drive it!!! Imho. pdq67
 

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Well, lets put it this way... if you want to go into the 10's on a 3500 lb car, it will take a minimum of 480hp to do it... it doens't matter if you make 300ft-lbs of torque or 500, it take 480+ horsepower. Having the torque in the right rpm band will make that 480+ horsepower, but if you have killer torque at 2000rpm, but it falls off by 4000, you can't make the horsepower, since it's a factor of rpm. A good example is the olds 455 motors... good torque... no horsepower... slow in the 1/4 mile in stock form, 15.1 second ride. (no, that wasn't a shot at old's-- they can be made to run with enough money, heck, we've got a 71-442 sitting here now). Torque is great, don't get me wrong, it makes for good burnouts, but to build torque at the price of horsepower is not the way to win drag races... especially in a lighter car that doesn't need it. Ever look at a super comp dragster... a lot of them run destroked 400 sb motors in the 330cid range. (and other variation, big blocks too)... it's all what you like I guess.
 

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Hey Eric, if you take that 317 rear wheel HP figure and divide by .71 like I was told when I had my car on the chassis dyno. You come up with 446 crank HP. Thats not too far off.

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Black 69 camaro
 
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