proper tuning...maybe 5whp..maybe

 

with a single cam you can really tune the cam timing for valve overlap like you can with a dual cam however it pretty much shifts the power band up or down.
Robster

 

Robster meant to say you cant tune overlap.... with a single cam olverlap is detarmined by the cam designer unlike DOHC engines... tuning overlap is a really great advantage because the more overlap you have at low rpms the intake charge is contaminated with exhaust gases in which you lose power but at higher rpms the vacuum from the exhaust gases exiting the chamber helps to pull in the intake charge increasing power...

 

yeah thanks for pointing out that typo musta been drunk or tired..........wait a minute arent i always