Trouble tuning 340.

You have some really odd numbers there.

You are going to WOT when doing the compression test I hope?

14-15" of vacuum & such low cranking compression sounds to me like broken rings......or the compression ratio is very low. Doubt it is a cam timing problem with 15" of vac, but severely worn lifters/lobes might give low compression readings. I doubt that a 'tune up' is going to fix this problem.