Anyone here done any porting or polishing on 8v heads?? I was talking to my cousin who races bikes and is part owner of a shop in the chitown area. He does a lot of cycle heads ( Kowalski sukuki and Yamahas) and suggested some stuff. He believes that the bowls on most Japanese 4s are pretty good to begin with. He thinks that just matching ports and cleaning up a little is about as good as you can do. But he thinks a 1mm bigger intake along with the valve job will give more torque. I don't believe it could be low end but maybe mid range. He said on his 750 race bike he could really feel this mod when he came out of corners so it wasn't just top end. Of course one wonders how much you can generalize fron bike to car but they are both water cooled 8v 4 cylinders. And 1mm doesn't seem like it would kill velocity . . Any thoughts??

Air flow is the key to performance.  You can gain a bit from match porting, smooth transition from intake to cylinder head to exhaust.  The best way to look at air flow is smooth unrestricted passage.  Any turns, bumps, sharp edges will effect air flow.  I have a great deal of experience with performance engines and tuning.  All of my Samurai and Sidekick projects have been left basically stock.  What do you expect to gain?  At what cost?  Cylinder head work can add up.  Most people are lucky just to keep the vehicle running properly.  A good running and dependable vehicle is what you need on the road and trail.  My green '86 Samurai that I wheeled for several years had the stock engine, NO K&N, header, or anything.  I added  Toyota power steering and drove the vehicle.  The best performance gain for a Samurai is an engine swap.  The same is true for the Sidekick and Trackers.  Early models can benefit from later model transplants.  Most don't just drop and plug in.  You need to do your homework.  Keep us informed on your build.