I've known Jim Grubbs, Jeff Latimer, and Ryan Peart of JGM Motorsports for many years. We've built a lot of engines and had a lot of fun together. Most of what we build together are warmed-up, ...

If hardened valves and valve seats were fitted in the rebuild, you wouldn't need to use an additive, but it's probably unlikely that they were, so it would be best that you do use one. Adding it won't ...