I'm looking for some timing specs on other engines (performance and sport engines). I have a fresh rebuilt TT .40 that i'm breaking in and I would like to do some small mods to it soon.

I've done a lot of reading on understanding how all they work, pipe timing and such. But I don't have any real numbers to go by?

I know some people say it's not worth tweaking an engine and I totally understand. But for a sport plane (viper) i'd like to do some testing for fun. Anyone have some numbers or a range I should stay in. I know raising the enhaust timing will help with the pipe but how much?....Thank you any info/ pointers would help.

Russ