255/60/15 ET streets?

69 valiant, no tubs, offset shackles, centerline 15X8.5 rims, has bfg ta size 295-50-15 under it. dart wells are a little tighter i think. but 275-60 ought to be do-able. understand, these were not the spring location kit that puts the spring into the frame rails. this set moves them over about .75 per side.
good luck with it, alan