2.76 gear top speed?

[mopar367]

i have a 360 engine pushing around 280 ish horsepower. with a 727 trans. and an 8 3/4 rear end. i currently have 3.23 gears but was considering putting in a 2.76 pot to get some top speed. and my tires are 28" tall et streets. does anybody run a similar setup and what kinda top speed could i expect?

 

[b-bodyboy]

According to my friends speedometer my 273, 904,2.76 b-body with 265 50 15's (shorter than some 14's) will go more than 140 mph. that wasn't all she had but not knowing the engines previous history kept me from turning it past 5000. an educated guess for your outcome is 160mph depending on what car this running gear will be in. this is just speculation im no engine builder.

 

[68X426]

The calculator says 196.26 mph at 6500 rpms and 211.35 at 7000 rpms.

The numbers that matter are 1.00 final drive, 2.76 gears, and 28 inch height.

With 3.23s it is 168 mph and 181 mph respectively.

In a perfect world (no friction and 100% efficiency) you can get there with one horsepower or 10,000 horsepower. It may be getting there slow or fast, but it would still be 211 mph.

In the real world you have to account for type of roadway, road friction, air friction, tire quality, brakes, suspension, car weight, and driver's balls. Obviously less than 211 mph results in the real world.

In your case, measure the performance capacity of your tires, suspension and balls and it's likely a top speed of 120 mph, no matter what your motor is doing, and with either 2.76s or 3.23s.

:3gears:

 

[MoparBill]

68X426- I was thinking the same thing- with 2.76 gears and 28" tires, most people will run out of balls or open road before the car runs out of top end.

 

[Hemifried]

i have a 360 engine pushing around 280 ish horsepower. with a 727 trans. and an 8 3/4 rear end. i currently have 3.23 gears but was considering putting in a 2.76 pot to get some top speed. and my tires are 28" tall et streets. does anybody run a similar setup and what kinda top speed could i expect?

My 67 Belvedere has a 440 with 727 and 2.76 gears and 255/60/15 rear tires (27 inches tall) and makes 298.9 rwhp on a dynojet dyno. Fastest its ever showed me on the garmen GPS was 142 mph, mind ya it was me that set the limit, the car had more but it was a scary ride over 135!! I do not recommend this kind of driving on a public roadway! keep your foot out of it and don't make this your last thread! lol

 

[shag766]

68X426- I was thinking the same thing- with 2.76 gears and 28" tires, most people will run out of balls or open road before the car runs out of top end.

X2

 

[mopar367]

true enough, i may be better with the 3.23s anyways. i dont want to be doing over 120mph in my old truck. she might come apart.

 

[Randy73]

i have a 360 engine pushing around 280 ish horsepower. with a 727 trans. and an 8 3/4 rear end. i currently have 3.23 gears but was considering putting in a 2.76 pot to get some top speed. and my tires are 28" tall et streets. does anybody run a similar setup and what kinda top speed could i expect?

In my 93 vette w/2.56 gears and a little over 300rwhp I could barely hit 165, what most people fail to take in to effect is that as you go faster the the amount of horsepower needed to overcome the air pressure goes up signifiently as you go into the 140+ range. I watched a car w/2.33ish gears (do not remember the exact number) with 400+hp go just over 230mph at Bonneville. And that car was shaped something like a bullet. Drag coeffeciency is almost as important as HP at high speeds, ask any formula mechanic. You do not say how much your car weighs, but if you want to find out without actually going out and doing it, find a calulator that takes in drag, tires, gears, final drive gear. HP and weight and you will get a good estimation.

My car may have gone faster, but it had 138k miles at the time and I do not know how level the road was, as this was late at night. Also, this was in FL and mid summer, so it was a humid night. I know cars have more hp in cooler, less humid climates, so I am not stating that you should not use my example as a rule of thumb, but hopefully I gave you an idea.

 

[rumblefish360]

In my '73, 4spd Cuda w/ 2.76 gears and a 28 inch tire, 155 was achieved @ (around) 6800 RPM's. Factory tach is taken with a grain of salt.

 

[A383Wing]

Play with this and see what you come up with...be honest on your input values such as what RPM you will turn your engine..total horsepower does not factor into the calculations

http://vexer.com/automotive-tools/speed-rpm-calculator

Bryan

 

[67Charger]

http://craig.backfire.ca/img/drag-eqn-2.png

Use your HP, frontal area (about 25) and drag coeff (about .40)

 

[Randy73]

http://craig.backfire.ca/img/drag-eqn-2.png

Use your HP, frontal area (about 25) and drag coeff (about .40)

That is based on rwhp, correct?

 

[67Charger]

yes, power at the tires

 

[V-Code]

http://www.youtube.com/watch?v=33jNxVXh-hY&feature=related

pay attention from around 2:20 onward .. the veyron SS needs 200hp to go 5mph faster than the veyron

 

[rumblefish360]

I seen that on TV. Cool stuff. When ya get going that fast, ... whew! Yea, big HP numbers mean little in the way of added speed.

 

[yellowdartdave]

I get about 185 outta 162hp.

This car that I hauled was good for about 230. Porsche 962C IMSA Prototype