<VV> engine noise

[Timothy T Werner]

I am just now getting the Monza back on the road after a long winter in
storage, and getting a noise from the right side of the motor.(110, dual
exhaust) Under load, acceleration or climbing a hill, I get a loud
"cracking" sound almost like an exhaust leak on the right rear side. No
sign of it at idle or cruise. It is idling a bit rough.
Looking underneath, I see no obvious holes in the exhaust system. Air
cleaner is OK, oil levels OK.
I have about 10K miles since replacing both heads, clutch flywheel
pressure plate, throwout bearing and pilot bushing. any ideas where to
start?
Tim