Living with 3.91's

middleagecrisis said

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!

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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!!!