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Old 04-29-2002, 12:05 PM
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Talking What is a good Gear Ratio for street use ?

What Rearend Ratio do most of you guys use. The car is a 3900# 1976 Chevy Monte Carlo with a
300HP chevy 355CI engine, TH 350 w/ 3000 Stall Converter and 10 Bolt Posi Rearend. I was thinking about 4:11 gears, but, it seems many street cruisers are now using 3:73 or 3:55 ratios. Will the 3:73/3:55 ratios get the small block into the Max power range quickley ?
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Old 04-29-2002, 02:46 PM
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you lookin for balls out torque and off the line power but no gas mileage and no high end for highways then go with the 4 11s you want gas mileage and goos RPMS when driving around street go with lower gears the most popular gear is 3 55's now, i have a friend with a 355 in his 81 camaro with 10 bolt posi wih 342s and lest just say he hasnt lost any races as of late with any cars and haha he just got courted for doin 165 in a 45 oooops haha
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Old 04-29-2002, 02:54 PM
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This is a situation that always presents itself when building a car.

Either you use what you learn from someone else’s build up and copy it for your car, guess at the combination and hope for the best (this can be expensive) or enlist the services of an every day computer to predict the best setup.

Based on tire size, transmissions gear ratios and differential ratios it hard to guess at the best combo.

Now add all of the other factors in such as weight, horsepower, torque and where they occur in the rmp range and then on top of all that aerodynamic drag, tire size and type.

With this in mind, Hotrodding a car can be a real guessing game leaving you with allot of unknowns.

If you would like, I can run the numbers on your car through a program called PC HOTROD and generate a complete performance report specifically for you car.

If this is something you are interested in, email me at the following address and visit this website:

pchotrod@hotmail.com

www.pchotrod.com
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Old 04-29-2002, 03:09 PM
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Keep in mind you need to keep your stall converter in mind when changing gears. I don't think it would be too good for your trans to be cruising down the highway at 2,300rpm's with a 3,000rpm stall converter (a dyno sheet won't tell you that). So you don't want to go too low. Unless you've got a real hairy cam you shouldn't even need a 3,000rpm converter, with a lower stall speed you could go to a lower geared rear. Either you're making a weekend racer or a reliable cruiser, I try not to mix them. Moderate cam, low stall speed converter, highway drivable gears, or big cam, high stall speed, and some kickin' gears. But that's just me and we all think different.

[ April 29, 2002: Message edited by: dmorris1200 ]</p>
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Old 04-29-2002, 05:26 PM
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If you have the option to change the tranny too, think about a 4-speed with an over drive.. The gearing is usually better in first gear as well as fourth. Just for the sake of argument, compare a TH350 pushing 3.73:1 rear gears and a 700R4 with 3.08:1 rear. Both of these combos have the same final first gear ratio, but the 700R4 is gonna let your engine run at around 1800 RPM on the highway. Compare that to the 3200 or so that the TH350 is going to give you, multiply the price of gas and head on down to the tranny shop. Just kidding. But if you have the opportunity, think about an overdrive. And I don't think you're going to have much trouble with a 700R4 with 300 HP.
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Old 04-30-2002, 04:17 AM
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I pick up a bit of sour grapes in your comment dmorris1200. The program I am referring to is not a dyno sheet but rather a complete physics model that calculates the necessary specifications of a car and reports performance accordingly. Sure it will not tell you not to use a converter that has an operating range at or reasonably near your cruise RPM. It also would not tell you to avoid installing a 1050 cfm carburetor on a stock 283 chevy motor. Some things are clearly understood.

What it will do is streamline your efforts and your Hotrodding budget by allowing you to experiment with numerous engine, body, transmissions, tires and gear ratios before purchasing and changing the actual parts. This in turn will allow you to pick the best combination of parts the first time.

This has been proven by numerous hotrodders over the years through the building of their cars.
<a href="http://www.pchotrod.com/Clients.htm" target="_blank">http://www.pchotrod.com/Clients.htm</a>

Programs such as this allow you to use the power of a computer for something better than playing a friendly game of computer Solitaire or sending simple emails. Computers today are more powerful and have capabilities far greater then most people realize.

Take advantage of that power-house of a computer you are using right now and put it to work for you calculating the data for your Hotrod.

I understand that computers can't take the place real know-how but they can be used as a technical tool to help determine what combination of parts will yield the best performance out of your Hotrod. Lets face it, we all want the best out of our Hotrods. Hotrods should not only look the part they should also have the true capabilities of a Hotrod.

The link below has examples of Hotrodders and their cars that benefited from using computer based automotive performance programs to calculate the performance of their cars.

<a href="http://www.pchotrod.com/Clients.htm" target="_blank">http://www.pchotrod.com/Clients.htm</a>

[ April 30, 2002: Message edited by: PC Hotrod ]</p>
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Old 04-30-2002, 05:01 PM
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I understand what you're saying PC Hotrod. Unfortunately in my opinion (and thats all it is) too many newbies spend way too much time focusing on dyno figures and engine horsepower ratings without really understanding the hole picture. You'd be amazed at how many guys I know that have burnt up transmissions and never even knew why. I was just trying to point out the relationship between the rear ratio,engine rpms, a 3,000rpm stall converter, and a transmission that might not last a year before it's burnt up. Didn't mean it as a personal attack at you just trying to explain the concept above.
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Old 04-30-2002, 06:03 PM
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pc hotrod,dee the morris,howdy! lets see now,sour grapes,hmmm?well it seems the fox wanted some,but alas,they were out of reach so he just decided they twerent[emphasis on the "t"]no good so therefore they must be "no good"[kinda like i feel whenever i read about a $ 175000.00 ferrari modena or some such.]anywhoo! back to the real question,"what gears"?.[by the way mr.wagon,vic., that is.,how many rrrssss[rpms] do you reckon your friends ride was turning with them there 3.55 gears @ 165 mph?]bigjoedo,thats a heavy sled,but the question is whether you want around town performance or hi-way or in between?regardless, you dont want to go below 3.73 if you want to feel some steam.understand i'm talking about a three speed auto,no od[budget stuff] if on the other hand you want to dream check out gear vendors under/over setup [www.gearvendors.com, i think?] well i guess that was my dollar two ninety eights worth.see ya!jimm
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Old 04-30-2002, 08:11 PM
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I'd have to say for just cruising around waiting for the next victim i'd go with the 4.11's .If your going to be driving on the highways mostly I'd go with the 3.55's or 3.73's,RPM'S will be lower and a little better gas mileage,but still have the power.(that's just my opinion)Me i'd take the 4.11's piss on gas mileage I don't drive mine that often.
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Old 04-30-2002, 10:17 PM
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PC HotRod,

After reviewing your site and looking at all the data presented I have a question. Does your software predict gas mileage? This is one of the areas in question here because gear ratio directly affects the fuel mileage of the vehicle. With some BSFC numbers it would seem to be fairly easy to generate a prediction. Most well equipped dyno shops will jet their engines using these numbers and are provided alongside the dyno chart at different rpm levels for comparison with volumetric efficiency, this is a direct determinant of the fuel consumption of an engine and the vehicle it is installed in.

Just curious?
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Old 05-03-2002, 10:33 AM
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No answer? maybe just interested in advertising his product not helping us rodders out? What do you guys think?
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Old 05-03-2002, 03:27 PM
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Ouch, I thought I was rough. Well all I can say is I hope PC responds, I would like to here his side. I have seen him post many times to e-mail him for hp estimations and dyno results. I assumed he was offering his help for free to our members and maybe hoping for a little bussiness at the same time. So my Question would be has anyone actually e-mailed PC Hotrod, and did he provide you the information offered for free. Personally I think being able to look at two graphs to see where my torque curve goes by changing cam specs for free is a nice offer. My only problem is using that information without understanding certain basics first. When I was young I would look at stuff advertised and buy it and not be happy later. It would be like reading an article stating that the 850 double pumper produced X amount of horsepower gain over a 780 Quadrajet on a dyno and thinking that's what I need for power, then buying it and putting it on a stock 305ci two-barrel engine with an auto trans and a 2.73 rear. BIG MISTAKE! It would be like a doctor performing surgery without knowing how to use a scalpel. Why would you offer advise on a good set of highway gears, gas mileage, etc., without questioning a 3,000rpm stall converter which he apparently didn't even have. He posted on April 29 [quote] 300HP chevy 355CI engine, TH 350 w/ 3000 Stall Converter and 10 Bolt Posi Rearend. <hr></blockquote> then on May 1 posted [quote] 300HP chevy 355CI engine, TH 350 w/ Stock Converter and 10 Bolt Posi Rearend. <hr></blockquote> in a different topic .
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Old 05-04-2002, 01:08 AM
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Sorry guys, I am interested in helping out my fellow Hotrodders and not just promoting this product. I am a true Hotrodder at heart.

To answer the posting, PC HOTROD v2.19 does not have the ability to calculate gas mileage at this time. A future version will have this feature activated but is currently undergoing extensive testing.

If you would like your information run through PC HOTROD I will be glad to oblige. Send an email to the address listed I will return a complete performance report.

pchotrod@hotmail.com

We can also take a stab at calculating your gas mileage.

This will be the first time we will have done this for the public; so far all testing of this has been kept in-house.

We are Hotrodders and are committed to the hobby.

Sorry to give you the impression that we are only in it for the money. PC HOTROD was designed with the expectation that this would be done for enjoyment of the sport and if money is generated that's fine too.

Additionally, please make note that when you see my postings I always volunteer our services.

We are currently setting up to work a local car show this Saturday to allow car show visitors and Hotrodders alike to run their own cars in PC HOTROD.

Sorry for the bad impression.
Sincerely,
JCE
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Old 05-04-2002, 02:19 AM
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Thanks for responding PC. Should have mentioned where the car show is.
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Old 05-05-2002, 05:27 AM
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Yes I should have, my bad.

The car show was established to gather funds for St. Philip Neri School in Metairie, LA. I'll try to post these shows when I hear of them.

I hope that I have regained the respect of Hotrodders.com bulletin board members with my response.

We really do have good intensions.

[ May 05, 2002: Message edited by: PC Hotrod ]</p>
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