391 gears with 295 50r15 tires

[rt green]

is anyone running this? what kind of rpm can i expect at 70mph vs 323's?  440 motor 4 speed

[cdr]

3470 rpm-----------2867

[Cooter]

28" tall tires and 3.91 gear at 55-60 3000 rpm. (727 3-speed)

[rt green]

thanks. so much for mpg.

[moparguy01]

but a 295 50 is only 26.6 inches tall. should be about 3200 rpm at 65 mph according to my math

[Cooter]

I managed to sqeeze out 11 mpg with 505 stroker at 3000 rpms for 47 miles...

[Cooter]

but a 295 50 is only 26.6 inches tall. should be about 3200 rpm at 65 mph according to my math

In a perfect world yes. But many here run high stall converters which effect real world rpm.
I was under the impression that the 295/50 was the same hieght as the 275/60 just wider.

[john108]

275-60-15 = 28"  tall
295-50-15 = 26.7 tall

[squeakfinder]

    I had that combo with an automatic (727). It was no fun on the interstate.

[rt green]

ok, same question, but what if I sprung for a set of 354's?    2900?

[cdr]

3.54     3150 rpm @70

[cdr]

3.91 3470rpm
3.54 3150 rpm
3.23 2867 rpm
all @ 70 mph 26.7 tire

[myk]

    I had that combo with an automatic (727). It was no fun on the interstate.

I'm running a 2.76 and I still don't like it.  Someday I will have to get a Gear Vendor's unit...

[cudaken]

Bruce, try this link.

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

Even has a Charger Dash! 

 
I'm running a 2.76 and I still don't like it.  Someday I will have to get a Gear Vendor's unit...

MKY, I run 2.76 Sure Grip in the 69 Charger and love the interstate! What do you want to do, run 70 mph at idle! 

Cuda Ken

[myk]

Bruce, try this link.

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

Even has a Charger Dash! 

   
I'm running a 2.76 and I still don't like it.  Someday I will have to get a Gear Vendor's unit...

Myk, I run 2.76 Sure Grip in the 69 Charger and love the interstate! What do you want to do, run 70 mph at idle! 

Cuda Ken

Lol yeah sounds good to me!  I know it's an unfair comparison, but my '99 F-bird can cruise @ 70 at 1500 RPM and that's just spoiled me completely...

[rt green]

I do have a cast iron 833 overdrive out of a 2wd gm pickup. I suppose when I hit 4th gear at the dragstrip  it will be a letdown.

[Dino]

I had 3.55's with 26" tall tires and I could not get that gear swapped soon enough.  Way too much rpm for anything over 40 mph.

[Cooter]

I do have a cast iron 833 overdrive out of a 2wd gm pickup. I suppose when I hit 4th gear at the dragstrip  it will be a letdown.

The trouble with the OD trans is the super low first gear and wide ratios. Think dump truck trans.
People have gotten spoiled on low cruise rpms.
I can see future threads now...
" guys, I got this Super comp stroker engine that lopes until 2000 rpm, and only gets 7 mpg in OD. What gives???"
You simply cannot run a camshaft ad big as some I've seen here at cruise at only 1500 rpms...
The engine is below its peak power making and efficient rpm. This is why many newer cars are going to forced induction with VVT.

[myk]

I had 3.55's with 26" tall tires and I could not get that gear swapped soon enough.  Way too much rpm for anything over 40 mph.

I always wonder how "they" drove with those setups, BITD...

[Brass]

I had 3.55's with 26" tall tires and I could not get that gear swapped soon enough.  Way too much rpm for anything over 40 mph.

I always wonder how "they" drove with those setups, BITD...

What RPM range do you guys like to cruise at?

[myk]

Depends on the car.  My 90's cars (Mustang, Camaro, F-bird) will do 70MPH at a little over 1K RPM.  Of course, they're all running freeway gears; 3.08, 3.23 and a 2.73 respectively.  The Charger on the other hand, I like to run it at 60MPH at 2400 RPM.  60's fine and all, I guess, but sometimes I'd like to move it a little faster and that's when I start moving into the 3K RPM range; not too pleasant, IMO...

[JB400]

I watch the tach to see what rpm the trans shifts at to determine where to run the engine.  Of course, that's with a light foot in normal driving with a stock trans.

[Dino]

I had 3.55's with 26" tall tires and I could not get that gear swapped soon enough.  Way too much rpm for anything over 40 mph.

I always wonder how "they" drove with those setups, BITD...

What RPM range do you guys like to cruise at?

2000-2500 range I would say.  I don't have a tach to confirm but the engine sounds just right doing 60.  On the freeway at 70 it doesn't go up all that high but that's thanks to the 2.96 gears.

I lose power off the line but for a daily it really doesn't matter.  That said, I can't wait to stick a T-56 in that car, that way I'll have all I want and then some.

[Cooter]

Trust me gentlemen.......
A .68 od with a purple shaft .484 284 (241 @ .050 dur). And 3.23 gears even with a 440, I have to down shift upon long hills.
Long duration cams an od trans do not mix.

[Dino]

Trust me gentlemen.......
A .68 od with a purple shaft .484 284 (241 @ .050 dur). And 3.23 gears even with a 440, I have to down shift upon long hills.
Long duration cams an od trans do not mix.

Very true.  I have the same cam and one day it will have to go.  It's just not the right one for my driving style.  Sounds like a mean sob though!