Knotshore 1 Posted October 9, 2014 hey everyone, so ive purchased an xf as a parts car for my xm. plan is to use everything i can (front brakes, engine, t5, and rear diff). my question is how strong is the xf diff in all honesty, i know this sounds like such a stupid question but the car isnt planning on getting thrashed (often) okay so it might a little. ive noticed the trend is to upgrade to an e series diff but at the moment i would like to work with that i have. cheers, stuart. Share this post Link to post Share on other sites
steve mcqueen 1,796 Posted October 9, 2014 Yeah wow. First off, the XF sedan has coil over suspension and the XM has leaf springs so thats gonna need big mods. Tho if its an XF ute or wagon you mite, mite be in luck??? The XM has a short narrow diff in it and the XF has a big longer diff in it, so your prolly have to pump your rear quaters or narrow the diff??? XM falcon's had drum brakes and most XF's had disc brakes, so you will need the booster to. If you have to go to extreme mods then you wouldn't waste your time. You would find an early diff from a Mustang and adopt that bad boy in instead. Front brakes mmmmm, you need a kit for these?? Actually, id check out the Castlemaine Rod shop for front and rear brake kits. Will the T5 even fit in that narrow as hell tunnel? Only a small hand full in here own early Falcons, but they do have knowledge. Perhaps check out members cars in the Early Falcon Car Club. http://earlyfalconnsw.blogspot.com.au/ 1 XTREME KARTS XF reacted to this Share this post Link to post Share on other sites
wagoon 2,429 Posted October 9, 2014 The reason for the upgrade in an 80's x series is that it is cheaper to change the diff than to upgrade and you go from 25 spline in 80's diffs to 28 spline in 90's. You also go from 2 pinion in the 80's diff to 4 pinion in the 90's diff plus all the 90's diffs have disc brake. And in general the cost in parts isn't huge to change them over. Yes the 90's diffs are stronger but unless you plan on clutch dumps, massive burnout and to have the engine producing lots of torque you can make an 80's diff last. Like any modification you make, know the limitation and nothing will go wrong. I can't help you in regards to what is needed to actually put one in an early falcon, there are others that will help there. 1 steve mcqueen reacted to this Share this post Link to post Share on other sites
Knotshore 1 Posted October 9, 2014 it is a ute diff just to clear that up. the front stubs bolt in reasonably painlessly apart from a sleeve, its rather cool. if you have a spare few minutes google it. Share this post Link to post Share on other sites
Thom 6,654 Posted October 9, 2014 Personally I'd shorten an e series diff (if you have to shorten one why not pick the better option) wider choice of ratios and more commonly available parts now days compare to the XF diff, what brake master and or booster setup are you planning on running? Is your car an automatic or manual car? Share this post Link to post Share on other sites
