Thanks for the respones....

It actually turns out to be both carb and lifter.
I had the rocker arms way too tight.
Changed them all to 1/4 turn and they are fine now.
I had always adjusted them the Old School way
while the engine was running in my younger days.
I also know that my carb is running a bit lean but
that's easy to fix with a pair of screwdrivers.

This engine is in a 1970 Chevy Caprice Classic Sport Coup.
73k original miles. 454 (30 over now )
I've had her on jackstands for 3 years and just now
finished with the rebuild.
Although I switched to headers, I am trying to keep it
somewhat stock looking from the outside.
You can't see most of what's been done.

New: Keith Black pistons, GM Performance cam and lifters,
new timing set, oil pump, water pump (GM cast from YR1),
p/s pump, full length ceramic coated headers.
block magnafluxed, bored 30 over, fully balanced.

I'll have her road worthy by the weekend .

Thanks for the help.

BudlyUSA