The same engineering that went into the design of the Superglide was used to improve the Powerglide tailhousing. A strengthened housing with a needle roller bearing yoke support was needed to go along with the increased horsepower and performance being produced by todays engines. A vent was also added to cure the common problem of trans fluid spraying out of the stock transmission vent when the trans gets hot. Installation of this housing requires extra care. The I.D. of the needle roller bearing in this housing is 1.500 in. Dedenbear wants the yoke to run with .001 to .003 in. of clearance. The yoke may have to be polished for correct clearance as long as there is no wear showing on the yoke.