[Brian]

Try this; remove timing cover, line up your existing timing marks, undo the 4 bolts holding the camgear on. Remove cam gear. Replace gear after moving cam [edit]clockwise sufficient to be able to bolt gear back on with its timing mark one tooth to the [edit] LEFT of that on the crank gear. bolt everything back. You have just retarded the cam [and timing] by 16 odd degrees. See how it runs now. Good luck