How often to freshen a 604

[PushinTheLimit]

I'm considering getting mine done before I start racing this year. I bought it used with the car I bought and going by the kind of seals I have on it, it's been at least 4-5 years since it was opened up by an engine builder. I've only put about 30 nights on it total since I got it in late 2013, but I have no idea how many is on it from the previous owner. How often do guys typically go between refreshes?

[Matt49]

I'm considering getting mine done before I start racing this year. I bought it used with the car I bought and going by the kind of seals I have on it, it's been at least 4-5 years since it was opened up by an engine builder. I've only put about 30 nights on it total since I got it in late 2013, but I have no idea how many is on it from the previous owner. How often do guys typically go between refreshes?

The best way to tell how well it is holding up is to run a cold leak down test. Anything over 10% and you should think about having it freshened up.