I wouldn't without getting the walls checked.... Add that making the walls
thinner has somne far reaching effects.... mechanical and thermal stability
suffer (all that cast iron vibrates like a tuning fork when the engine is
running)... we are one step closer to the possibility of a catastrophic
failure....

There are a lot of trade-offs when rebuilding a motor.... just because you
CAN go 0.040 over, doesn't mean you should. Sometimes we can consider our
end use in our decisions... I might consider 40 over on a seldom driven
toy... but the idea that this could be a grenade if I built the top end too
strong and got frisly would be there.

At the same time, we are building a 500 inch RB Dodge that has had the
cylinders bored crazy..... Again, if we trash this motor, my friends is
flush enough that it wouldn't be a lifestyle altering deal.

Something to consider.... There's a chance that I'd buy a 40 over W block
351.... but I wouldn't consider anything other than a block that has been
freshly bored by a reputable shop using good torque plates. What I wouldn't
buy is a 30 over block with 70K miles on it without measuring out of round
and taper and probably deck heights.

Consider this... "flush" race operations keep careful track of things like
rotating and reciprocating parts.... they know that these pieces have a
finite life and they choose to replace them before they fail.... There is a
ready market for most of these pieces with those willing to enter into a bit
of a gamble (and it doesn't hurt that they will likely be run in a set-up
that wont produce quite as much power as the original user is making.

It's a subjective decision... but for someone that may be close to spending
the rent money to fuel (pun intended) his hobby, I think it important to
build a real good bottom end first and then build from that. Or, if the car
isn't a candidate for cours d'elegance type viewing, perhaps it might be
time to introduce some new technology and build something both strong AND
dependable.