Alright, so i've got the stock ss, 3.08 slug. I'm going for a rebuild on my diff, with 3.7 gears and LSD. I have a 4L sedan by the way, with a live axle, and auto.

Now my launches are gonna be faster (right?) and my revs at cruising speeds are gonna be higher. Around 2100 at 100km/h? Right? Now I know my speedo's gonna be out, but i'll get that fixed.

One of my main questions, is whether i should put a tailshaft loop in, because the speed at where the tailshaft gives way, will drop considerably, because the gears are spinning much faster, at lower speeds?? Are there different types of tailshaft loops you can get?
Made of different materials? Where can you get them from?

Thanks

Tailshaft loops arent something I know too much about. Although I think I saw one on ebay for about 50 to 60 bux.

Yes, im no expert on tailshaft loops but i agree that your tailshaft's stress point will be at a much lower speed with 3.7s.

I believe you will need some reinforcing at the point the loop connects as the floorpans are not that sturdy.

You will most likely need an electronic speedo correction device as your ECU bases shift points on speed and will not recognise the higher engine revs....

Your 180KM/HR speed limiter should kick in earlier.. so theres no need to worry about breaking the 180KM/HR tailshaft shattering barrier.

True, so it will kick in about 150... 160km/h, unless i change the speedo gear to a more accurate one, Then it will go back to 180? So would it be safe to go over 150, with the new diff? Or do you only need to worry about tailshaft's in utes? Does anyone know what sort of tailshaft i have at the moment (AUIII Falcon)? Alloy 2-piece or ...? I'll most likely get the new diff over the next month.

Cheers

here i am looking at getting rid of the old 3.08 diff gears and putting in an lsd but i know ford did not make lsd diff's in 3.08 and only in 3.27 so what would be the rpm change in the standard 4l auto i know i will launch a bit quicker and do i have to buy the part that goes in to the gearbox or something like that?

thanks

Don't buy the diff through Ford, go to a Diff specialist and get them to rebuild your diff.

By the way, i think it was a 3.23 and it will only rev slightly higher. Maybe 1800-1900 at 100 km/h

it would be 3.27 if its a EB2 or ED, most ebs and eds run a 3.27 anyway so it is an easy change with all the parts readily available