I would need a 1/2 spacer. I measured the distance of the closest part of the fan to rad and it is about 3/4 in.Part of the problem witha spacer is that the rad sits at a angle to the engine. almost a 1/2 in closer on the drivers side. The motor is square with the crossmember . It may have taken a wack sometime in its life. Think I will try a shim on the pass side of rad. that will bring the fan tips to about 3/4 in . The stock fan sits closer than the flexfan did.