[miket1]

Sam, you are correct, I have had all my vacuum advance distributors plugged since 1970 and run only mechanical advance,they run much better, as I said earlier I need to fine tune this a bit more. If it doesn't dial in correctly I have a new MSD mechanical dist. I will install as they are very easy to dial in.
I have considered going the day 2 route w/ headers, no smog, etc.,really don't want that look, if I lose a few HP. because of restrictive exh. that's ok, I only drive my Z 50 miles a year.
The heat riser looks to be one of the most restrictive parts so I may try removing that.