As I undersrand it the roller lifters in an FE were a short lived thing, that may have changed. Some things would have to be changed in the
oil plumbing on my sideoiler block. Also I heard a 6,000 rpm limit for hydraulic roller lifters. I currently have my rev limiter in my Mallory HyFire VI box programed to 6,000rpm. As it is, it gets there so quickly that I forget to shift until it stumbles against the limiter.