455 w/ 200-4r question

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84cutspreme

Royal Smart Person
Jun 4, 2009
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Okay...my pops is trying to figure out what the best gear ratio in the rear will be for his setup. 455 olds block with est 496 hp @5600rpm. 200-4r trans. He want to be able to make track runs. He is torn between 4.11s or 3.89s. He is really just trying to avoid having to shift into OD to avoid over reving or having to let off the gas at the end of pass. So really question is which would be a better gear ratio 3.89 or 4.11 to stay in 3rd gear and not go to high in RPM. Cam makes power up to 6000rpm.
 
I'll assume 28.0 tall rear tires and 3,800 pounds with driver and fuel. But I will have to come back when I have time.
 
27.1" tall tires and car is 3750 lbs
 
I'd go with the 3.90 gear. That's what I run in my firebird with a 455 olds. Crosses the stripe at about 5500 rpm, 28" tire, th350 trans.
 
I will show you how to do it for yourself. http://www.wallaceracing.com then click automotive calculators. You will need two of them:

HP from 1/4 MPH and weight

and MPH - Gear ratio

HP from 1/4 MPH & weight calculator tells you ideal gearing (whatever that is) and what mph your 500 flywheel HP can push your 3,800 pounds to. answer 118 MPH. Don't worry about the ET blank just fill in MPH and weight blanks changing the MPH until it matches your 500 flywheel HP.

Then use the MPH - Gear calculatorto find what gear will put you at or closest to your maximum HP rpm ie 5,600.

Result 500HP & 3.90 gears on 28" tires (275/60/15 or 275/40/18 drag radials) can get your 3,800 pounds to 119 mph in the 1/4 or just past your 5,600 maximum HP rpm and would be for practical purposes ideal 1/4 mile gearing.

On top of that you can also put 2,200 rpms into the MPH - Gear calculator and .67 into the trans gear ratio box (for the 200-4R) to see that you would be traveling at 70 mph just puring along comfortably getting proably maximum cruising MPG (side benefit) out of a cam that is big enough to make 500HP from your 455. No taxing your cooling system and no spinning the snot out of your big block investment AND bad arse on the strip.

Now you just need traction (we will leave that for another conversation) and a good stall converter to match your cam etc. You probably have something around 230@50 duration or better to make that HP which would leave near maximum torque at around 3,000 rpms. For $300 bucks I had one of my factory 200-4R "D5" lock-up converters rebuilt & upgraded furnace braised etc to 3,000 stall. Some of the great things about it being a working lockup converter is that under normal part throttle driving conditions it drives as nice as a stock converter ie smooth, better mileage, and no excessive heat taxing your cooling system. All because its not slipping. Its only at heavy throttle when you bang out of the hole and realize with a big grin that you have a high stall converter. :mrgreen: 8)

On top of that the 200-4R is lighter has less rotating mass to spin up and is more efficient than old three speeds or most other overdrive transmissions. Its only challenge is that it has to be pro built and if you are putting it behind a 500+ foot pound of torque big block you need a billet forward drum. It doesnt work well in a heavy vehicle or towing situation either partly because of the small pan & limited fluid capacity. Sorry for the 200-4R commercial.

See why I say the overdrive transmission is the single best upgrade to a real driven hot street car. Three speeds are for drag/race cars or local only stop light to stop light cars or I can't afford better cars othewise they should be left in the 70s as they are that far out of date. Hope that helps and that I didn't bore you with too much info.
 
You know I have to laugh at that post only because my pops made me go on that wallace racing calculator last night...it was a mind @*$!, what he was trying to figure out was what rpm he would finish the 1/4 in with each setup. 3.89s or 4.11s (btw its a ford 9" rear) I also found them to be highly inaccurate. No matter what I punched in they showed the car running high 10s @ 117.27 mph. Maybe you can help me figure it out for him?
 
Well I made it stupid simple for you and told you the only two calculators you need for what Pops wants to know. Actually I pretty much already bottom lined the answer to what Pops wants to know in my last post. If you make the effort to read it closer and or try it. BTW not to be shitty or anything but the calculators are probably accurate and its your understanding of the data either in or out or what the calculator was to be used to tell you that is inaccurate. Best of luck.
 
While I'm no guru, you might look at something in the mid threes. 3.50 or 3.70. That engine should make plenty of torque to pull it and it keeps the revs down. The first gear is deeper than t350/t400 so you get that adavantage too. Just something to consider.
 
Thanks for all the input...my pops got frustrated already and decided to just go with 3.73's like he had.
 
Rich your not wrong on what you said. But take a few minutes to use and get to understand those two calculators and you will quickly become a guru on that subject.
 
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