anyone know if positive valve stem seals are avaiable that can be used on stock 351m/400 heads without turning down the guide? everthing I have read about positive seals on the 351m/400 heads involves turning down the OD of the guide, Why cant positives fit?

 

Not sure about that, try TMI if anyone would know he would. It wouldn't cost much to have a shop cut them for you or you could just buy a cutter and pilot in the size you want to use, they aren't all that much money and after your done with it you could sell it.

 

Thank you Mark,

The Cleveland head has a guide that the OD tapers.