Sorry, this is not my '69 Corvette with problem, but:

Recently my roomates 95 V8 Camaro failed smog ($69) with high emissions,
last year it was overhauled in shop.
Visual/Functional checks passed
15mph HC=181 C=1.13 failed
25mph HC=164 C=1.07 failed

I then took it for a diagnostic checkup ($90) and got the following results:
scope check found secondary problem, average kv to snap kv change low
found weak catalyst rec.
02 sensor heater wire poor insulation
egr sol. harness cut on arrival (connectors were mated by diagnostic
tech)

They recommended a tune-up, platinum plugs, cap, rotor and plug wires.
Check for intermittent or fouled sparkplug
plug wire for leakage to ground
distributor cap for arcing or carbon tracks.
Special Note: new sparkplugs may activate this message.

Note, no apparent driver warnings present such as check engine light.

I've removed only two plugs so far. Third plug back on driver side I could
remove from top but replace only from below. The fourth on driver side is
near impossible to reach. Haven't started on passenger side nor plug wires.

My auto parts guy says engine must be lowered to replace $200 cap/rotor.
These are covered by the firewall/dash/windshield. O GREAT. What engineer
should be congratulated for this fiasco? I've always admired the design of
the Camaro but never worked on one.

But wait. I am confused. The plug wires came from the front of the engine.
How does that work? Where is the distributor(cap/rotor) on this car? On
the crankshaft, at front of engine like the '95 Caprice or at top rear of
engine such as the HEI type?

Any advice?

Gary