So..... i just bought a 20b (c240 with black raised letters on the housings whatever that means)
and im gonna get it pinned/ported/balanced/clearenced/oil and water mods.

So i started thinking about the porting, my goal is a 500-600rwhp on e85 (gt4088r maybe)with durability and a broad powerband and a very responsive engine.

My builder suggest a early primary port opening and some exhaust porting with only a minor cleanup in the secondaries.
What do you guys think?

 

Honestly for time attack and a tight course I recommend stock ports. Most porting is for top end gains at the expense of bottom end and spool up time.

 

I would replace the exhaust port sleeves with FD ones, and otherwise just clean the ports up a little bit. For that power level you will have no problems with stock size ports, especially on e85.