ive got a 95 bird with an axel code of Y, ive looked it up on charts and its apearently a 3.08 and ive got a 96 bird parts car with an axel code of E with 3.27's...
Which one of these will give me better low end performance on a weekend cruiser and whats the difference between them?
i rarely see 50+ MPH in this car
The difference is .19 . (Kids these days, can't do basic maths.)
A distance that will take 3.08 engine revolutions on the 3.08 rear end will take 3.27 revolutions for the 3.27 rear end. A side benefit is that you'll be closer to the torque peak on the 3.27 rear end for the slower road speeds.
Good news - you don't have to change the whole rear-end, just the diff.
Better - an upper knuckle bolt each side, and you can usually shimmy the half shafts out. Four driveshaft flange bolts, and four diff bolts (don't forget the ABS sensors if your car has ABS!), and the diff will fall out if you're not careful.
Add a new VSS/speedo drive gear in the tranny (so the speedo is right), plus if you vary more than to the 3.27, I'd opt for a tune to get the shift points right with the electronic tranny you have (an AODE, IIRC. Might be a 4R70W).
The common gear ratio to swap in seems to be the 3.73. IMO that's the cutoff point between "daily driver" and "playtoy". (Then of course, my idea of a true daily driver may vary from another's. True daily driven = on interstates keeping up with traffic for 30+ miles.....others may be perfectly content to get run over while keeping their cruise @ 65 mph. In that light, 3.55s work best for me in my DD.)
But since you aren't hitting much above 50 mph and it's not being considered a DD, go nuts with a 4.10 or 4.30. Just do your homework and make sure you're doing what else needs to be done along with the relatively simple pumpkin swap.
For highway I love my 3.73s! 75-80mph is still quiet inside, and it brings the motor up closer to the powerband so it accelerates easily without having to downshift. I have driven my car on 600+ mile drives with the 3.73s, and at no point was I wishing I went with anything else.
-91 Cougar LS, coming soon, complete overhaul with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
-97 Tbird Sport 4.6 Nice weather daily driver
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