3:91's and Nitto P275 60R15's (27.9") for reference:
50mph @ 2600 rpms
55mph @ 2900 rpms
60mph @ 3100 rpms
65mph @ 3300 rpms
70mph @ 3400 rpms
Living with 3.91's
- Thread starter TimDart
- Start date
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50mph @ 2600 rpms
55mph @ 2900 rpms
60mph @ 3100 rpms
65mph @ 3300 rpms
70mph @ 3400 rpms
middleagecrisis
Well-Known Member
It's all about tradeoffs. Personally, 3.91/4.10 gears are my choice for old-school hotrods. I've run 2.73 - 4.88's on the street, depending on the engine and what I wanted at the time. Overdrive transmissions have made a running a deep gear much more bearable, if you can afford the conversion cost. Of course, I'm partial to a stout engine making noise at 3K rpm going down the road!
In my first '69 Dart I ran 4.88s on the street behind a stout 340 and a reverse-pattern-manual-shift 727. It was a lot of fun on the street but I didn't dare try to drive on SoCal freeways with that combo.
My current '69 Dart will run 4.30s behind a moderate build 360 and a reverse-pattern-manual-shift 200-4R overdrive trans. The 200-4R has a better gear spread than a 727 and the 0.67 OD will make those 4.30s like 2.88s so it will be freeway-friendly as well.
And, the 200-4R fits in an A-body trans tunnel without major modifications to the tunnel.
Granted, the conversion wasn't cheap but it will definitely be a Win-Win smilewise!!!
MidnightSwinger
Well-Known Member
I’ll never understand why spinning dead in the middle of the rev range scares people. 3k rpm is nothing for a V8. If it’s too loud change mufflers, or add resonators.
The Barracuda sounds glorious cruising at ~70mph and 3100 rpm. My *** gets tired of the seat long before my ears get tired of the exhaust. I can hear the am radio/single speaker over it no problem.
The Barracuda sounds glorious cruising at ~70mph and 3100 rpm. My *** gets tired of the seat long before my ears get tired of the exhaust. I can hear the am radio/single speaker over it no problem.
B3422w5
Well-Known Member
Put 3.91’s in it and buy a real convertor. Those changes will really wake up a stock stroke smallblock.
With a 28 inch tire you should be able to run 60 on the highway comfortably under 3k I would think.
If you want to go fast, you have to give up something, especially stock stroke.
I drive my car around a good bit with 4.30’s and an 8 inch vert, but I don’t use the car for highway driving, just around town and country roads.
Another reason I don’t drive on the highway I have skinny’s on the front and drag radials on the car, same tires it runs 10.30’s at the track without swapping tires back and forth. Not good highway tires, imo.
Again, what do you want, it’s all about what makes you happy
With a 28 inch tire you should be able to run 60 on the highway comfortably under 3k I would think.
If you want to go fast, you have to give up something, especially stock stroke.
I drive my car around a good bit with 4.30’s and an 8 inch vert, but I don’t use the car for highway driving, just around town and country roads.
Another reason I don’t drive on the highway I have skinny’s on the front and drag radials on the car, same tires it runs 10.30’s at the track without swapping tires back and forth. Not good highway tires, imo.
Again, what do you want, it’s all about what makes you happy
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