I've got a 69 multileaf rear end on my 67, installed by previous owners. I can't say the factory traction bars need to come off or not, but you can do without them OK since the multileafs will be less prone to spring windup under hard acceleration. You may need to get multileaf front spring perches (available from all the catalogs) but it doesn't look like any modifications are needed. The spring to axle attachment may be tricky - somebody else will need to talk to that since my springs match my axle. You run into wierd problems with the anchor plates due to 68/69's having staggered shocks. I wasn' t able to find multileaf anchor plates for non-staggered shocks. I ended up using 67 monoleaf anchor plates when I removed the aftermarket traction bars. The lower shock mount ends up lower but seems to work OK. My car came with aftermarket traction bars that bolt in place of the anchor plates which may be something you'd want to consider.