[PeteF]

Are you sure that firing order is correct for the cam that you have ? I seem to remember that 15426378 firing order is from the 260/289 engine, and that Ford changed it on later small block engines (302 or 351 ?) so that cylinders 7 and 8 were not firing one after another, to reduce local head temps. My memory is fuzzy, but check firing order. Good luck