valve covers that won't leak - ??

probably a semi-stupid question - and at the risk of starting something on here.. does anybody have suggestions/experience as to which covers and gaskets to use on a small block that won't leak?
Late comer to the thread.

Never an issue with my MP covers and reuseable rubber outside steel core MP gaskets. No sealent used. These gaskets also work well really well with the M/T, Holley/etc... type of aftermarket covers.