How many rpms am I running?

[miller]

I have a standard 727 and 2.77 rear gears, so how fast is my engine (440) turning at 40, 45, 50 in first gear?

Is there a ratio that i can look into ( My tach doesn't work and I was hoping to know exactly how fast the motor can turn before I put it into second gear).


My little 318 could get up to 60 in first gear, it was screaming but it managed, I'm not exactly sure the 440 could perform a similar task however.

[Troy]

What size tires?

Troy

[73chgrSE]

my 400 was able to do right at 60mph in first gear with 2.76's rev'n 5000.

[frederick]

Try this:
http://vexer.com/68rt/speed.html

Frederick

[miller]

So if I am getting this right, everyone out there running 3.91 with a 727 are turning about 4000 rpms at 60?

How do you guys take your cars anywhere!

[sixty8charger]

 and that is why i am saving up for Gear Vendors!

[73chgrSE]

i've got 3.73 and can still cruise on the highways @ 70mph @ about 3K which is a little high.  i couldn't imagine having a 3.91.

[ramairthree]

Most people I know that cruise highway style have maybe 3.23s or lower numerically.

If you want some sweet 4.11s for the quarter you will need to go to an overdrive transmission if you realistically want to cruise on the highway for other than a short trip

[Nacho-RT74]

those RPMs calculators are with tranny pulling out everytime with full throttle, but the REALITY is when you are on a highway, at maybe 50 Mph, you are BARELLY opening throttle, just enough to beat the inertia, never at full throttle, so you'll never get 3000 RPMs with 50 Mph cruise speed. EVEN LESS with that gear ratio... you'll be as much at 2000-2200

[miller]

those RPMs calculators are with tranny pulling out everytime with full throttle, but the REALITY is when you are on a highway, at maybe 50 Mph, you are BARELLY opening throttle, just enough to beat the inertia, never at full throttle, so you'll never get 3000 RPMs with 50 Mph cruise speed. EVEN LESS with that gear ratio... you'll be as much at 2000-2200

So you are saying that a 3.91 at 50 mph should make about 2200 rpms? So at 60 I would be going at 2500 rpms? That is good to hear. Thanks

[Nacho-RT74]

You said 2:77 gears, and sorry, I missread, I'm talking IN DRIVE. 1st Gear it could be 3700-4000

not saying that like a FACT, everything depends of your inertia and road conditions specs/slope of road. Remember ACCELERATION is not the same than SPEED.

I think I make around 3000 RPMs at 70-80 Mph with 3:55, 27" wheels IN DRIVE. but at that speed in Drive, engine/tranny is pulling, without lot of inertia really. At 50 Mph I'M ALLMOST SURE, barelly gets 2000 Rpms and tables say 2200... of course INERTIA helps. Once got the speed, just need to touch the pedal to keep on speed.

Remember I'm not an expert, those are just my overlooked observations when driving.