odd ball question of the day.

my boss has a 73 duster that he drag races . has a 400 block stroked to a 472. its an alcohol motor. now the problem he is having is new to me . after 3 1/8th mile passes the intake valley pan split down the middle. its about a 7in crack right down the center . this is one of the most bizzare thing ive ever ran into. any ideas on this one???

I've had a few of them split on me too. It's caused by pressure inside the crank case. The pan flexes up and down until it fatigues and splits along one of the creases.

You're probably getting a lot of blow by or don't have the engine properly vented.

Quote:

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my boss has a 73 duster that he drag races . has a 400 block stroked to a 472. its an alcohol motor. now the problem he is having is new to me . after 3 1/8th mile passes the intake valley pan split down the middle. its about a 7in crack right down the center . this is one of the most bizzare thing ive ever ran into. any ideas on this one???

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Pretty simple really... he is pressurizing the engine
with blow by... the crank case is building pressure
from the air passing the rings... put a gauge on
a valve cover to measure the pressure... a vac pump
will eliminate/correct the problem