Hi, I have 1991 z28 camaro with 305 engine and manual trans from Italy, sorry for my english...

The car have l98 stock engine with upgrade 58 throttle body air, 24 lb injectors, performance headers with full open exhaust (no cat) and k&n air filter.

The l98 have 6 grades of timing stock, can I tune up this? How much?

Thanks.

 

Typical static advance for a small block Chevy is 10-12 degrees. Try it, listening for detonation (spark knock) with the engine under heavy load at low RPM.

 

Ok thanks!!