Thanks Ted:



The vacuum reading is at idle 700 rpm.



I opened the valves up wider however the clatter got louder than I wanted to hear. On my other car that has the same Isky E4 I found .017 was the best for clatter, vacuum to a good idle. Less than .017 lash had a terrible rough idle. Isky specs say set .015 lash.



On another note for to get good performance and idle I have had to advance the distributor lots (MSD) advance set at 18 degrees vacuum line unhooked. Running blue stop with heavy silver and blue springs. If I reduce the initial advance it is very sluggish at low end, heavy idle and if I advance more will ping. Total advance exceeds 40 degrees.



I am going to see if I can borrow a wheel this weekend and advance the cam as it seems to be the culprit.



P.S. Just re-read your post Ted on opening up the valves and checking vacuum. Will do that before tearing front down



thanks marv