Best street/strip gear ratio

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cuda67

cuda67

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I have a 67 Barracuda conv't. It has a 360 roller motor with 390/400 hp. I had 3.91 gears several years ago but swapped those out for 2.93 for highway driving. I want to put new gears to restore some of the get up and go. What would be a good ratio? 3.55, 3.73 and still be streetable..
 
I drove my Valiant for almost four years back and forth every day with 4.30s and loved every minute of it.
 
How tall of tire, really can't figure with out that, short tire 3.73, tall tire 3.91 or 4.30
 
It depends on the rpm/speed you like in your street driving. Highway? The mini van moms will be passing you in the 3:91s. But if you just cruise to the burger joint go for it. Personally I have 3:55s. It's a pretty good compromise. Yeah I ran 4:56 and 3:91 on the street back in the day but with the traffic that would stack up behind me now...
 
B'cuda said:
It depends on the rpm/speed you like in your street driving. Highway? The mini van moms will be passing you in the 3:91s. But if you just cruise to the burger joint go for it. Personally I have 3:55s. It's a pretty good compromise. Yeah I ran 4:56 and 3:91 on the street back in the day but with the traffic that would stack up behind me now...
Click to expand...

You have to push the pedal on the right then you wont have traffic behind you.
 
A lot depends on the cam. It’s duration. If it is to large, then it will chug and buck if the gearing is to low. This is coupled with the tire diameter. Since you have been living with 2.93’s for a while..... I’d guess the 3.55’s would be very good. That’s the gear ratio I use in my Magnum with 245/60/15’s. I do not have a tach to watch. (Broken)
 
B'cuda said:
It depends on the rpm/speed you like in your street driving. Highway? The mini van moms will be passing you in the 3:91s. But if you just cruise to the burger joint go for it. Personally I have 3:55s. It's a pretty good compromise. Yeah I ran 4:56 and 3:91 on the street back in the day but with the traffic that would stack up behind me now...
Click to expand...

Piss on um. Let um line up. lol
 
Keep what you got
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3.91 gear is not that much more rpm wise than 3.55? I have heard it in past threads. Someone chime in please.
 
Anybody in your area you can go for a ride with? See how you feel about the high rpm stress vs the giddy up. Was the 3.91 with the same motor? I have 3.55 in my 69 cuda conv with 360 roller, running about 3200 rpm at highway speeds.
 
3.55 and 28" tall tire...stock wheel well ..68 cuda Great on the street.
I run 26" slicks when at the track.
 
You going from 2.93 to 3.55.... you're not going to feel much more "gitty up and go" after all the hard work .... money spent. 3.73 or 3.91 would be a good decision.
 
I am running 4.10 with a 27" tire as my daily driver. I tach a little over 4,000 in the 70-75mph range on my commute to work. It is not going to hurt a 3.31" stroke. I doubt it will hurt a 3.58" stroke, or even a 4" stroke.

It isn't your gearing which will destroy your engine in a street/strip car, it's the loose nut behind the wheel.
 
3.73 - Not a std. Mopar gear - if not available, go with 3.55. -- My 2 cents.
 
QuickDart360 said:
3.91 gear is not that much more rpm wise than 3.55? I have heard it in past threads. Someone chime in please.
Click to expand...

On the ratios, Do the math... in actual rpm changes, automatic cars have a variable that isn’t consistent. Torque converters.

3.55 - 3.23 = .32 difference
3.91 - 3.55 = .36
3.91 - 3.23 = .68
 
QuickDart360 said:
3.91 gear is not that much more rpm wise than 3.55? I have heard it in past threads. Someone chime in please.
Click to expand...
I have 3 :91s, the car does 3000 RPM at 65 MPH with the stock 14 inch ralleys. I can floor it at a roll and it will quickly get up to 90-100 without downshifting, but the RPM's are up there. Engine was a 318 ( I have since installed a 340 havent a report on it yet ) . I didnt have to downshift at all to slow down and make a turn, it is a 4 speed. Geared like a tractor it seems. Can someone describe 3 ;55's ?
 
I’ll describe my 3.55’s as a excellent acceleration improvement over the Hwy. gears and not rpm or speed limiting like my 4.10’s & 28 inch tires.

Reasonable Hwy rpm & speeds with this gear ratio. These gears will be really good if you have good torque behind them for acceleration. More torque the merry.
 
I have 2:73's in my 86 Mustang GT. I will say that the car is fun and economical, but not as fun as my Dart, and not "scary" fast either.
 
I run 3.21s and a 25" tire with an auto in the dart. If I had more tire, I would need more gear. I ran 3.42s in my Cutlass and liked it with 25" tire. If 3.42s were more readily available for mopar rear ends, I would use that.

Gear Ratio Calculator has a nice chart that helps figure out tire size to gear ratios...

sb
 
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