LocostUSA.com

Is there a thread (I searched.. no dice) that lists the following type of info

Name|Rear end type | offset|Gear Ratio Options| Track Width
Miata|IRS|No|3.9 4.1;55.6"

I am looking to find a new rear end option when I go from a book width to a +4 chassis

Thanks
~J

Solid rear axle thread if you haven't found it already
viewtopic.php?f=5&t=1231
Though if you're looking for IRS I don't know if there's a good single thread for that. I know the Ford center sections are talked about quite a bit.

Why not complete and sort out the drive train swap first?

Why do you want to increase the rear track?

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

There's very good info in that thread mentioned by Cardot60. In addition, depending on how much distance you want to cover, consider new wheels with offsets you specify on your existing, old rear axle. It's just another possible option to consider.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

Because I am cutting the car in half and making it wider. My goal is to align the motor with the rear end and if I get an offset diff- I'll need to position the engine to match

I want to widen the rear because I have a 14" passenger seat and 15" drivers seat and my tear has expanded so it isn't comfortable anymore

I've always wanted Sparco type seats so with a small trans tunnel (maybe..m) it.might be possible to at least get 1 good seat in

I do not know of any diff where the pinion is not offset in the housing at least a ½ inch. I suggest keeping the geometry you have front and rear. Then you only need custom longer axle shafts between the joints and a wider steering rack between the inner joints (assuming the current width rack is correct). The shafts should run about $250 or less, just fit new one-piece boot kits to the old joints.
If still want to change to a different diff, use google to search. The forum search doesn’t recognize 3 characters or less. I suggest the mid-90s tbird v6 7.5 irs with ratios from 2-5:1.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Thanks ! I've really thought about what you said and I agree on many ways. I'm going to try get the front all sorted out and when the engine runs I'll be in a better spot to decide the rear end. I think the replacement axles is probably the way to go. Even at 500 hp but less than 1300 lbs I would probably be gone and have traction problems long before.

Appreciate you drumming sanity into my head!