[98SteedaGT]

I wouldn't think so. The break in period allows for the crank to seat properly on the new bearings, and on center cam engines, it allows for the lifters to seat on to the new cam, etc... Since this is an OHC engine and you are only changing the heads, I wouldn't think that there is anything to "break in".. There might be some parts in the cam section of the new heads that might require it, but I don't know.... I would ask a Ford Tech or the mech you are bringing it to.