i saw somewhere, that mr gasket made some, anybody running them and if you do, do you need to get new pushrods and if so what length

 

yeah Mr. Gasket makes them, but they only list them for the Iron head cars. but people use the Impala gaskets all the time without much trouble so....
every car will be different, your best bet would be to check your pushrod length once you get every thing assembled, a pushrod length checker is only like $20 from summit