In my experience and what I've seen wrenching, carb engines ran dirtier than FI that lead to sludge and wear. Its typical to tear down a LA 318 from the 70s with less than 100 thousand miles and have to use a ridge reamer to get pistons out, not so much on a FI magnum . This applies also to any make carb engine really ford chevy etc. Any FI engine usually doesnt sludge up under the valve covers or not as bad as a 70s carb motor.