318 bogging at high rpm, but only in first gear?

Could be a fuel issue... but probably something like tons of leak down. The motor goes flat in other words. Valve springs and poor ceiling Rings will do that.

How about showing us the plugs?
How's the carb setup, jets n rods?
Are these valve spring to this stock or mild cam singles or have a dampener spring or?
Whats the cranking compression and have yo done a leak down test?


Faster it can rev up in a lower gear the more it shows up? Does it blow smoke out the breathers?