I agree with Mike and Jerry, I don't know if everyone will agree but I always use a static light then a timing light if I think it's necessary. On 216's and 235's I use the Heisenberg Theory. " After checking all possibilities one usually finds that the simplest is the problem." I find that we are all having problems with many parts from China regarding reproduction. Pretty much everything. Save your old parts guys the GM's are going to rise again. Doc