Factory z24 carby fuel screw setting

[Pinelli]

Is it worth trying the spark leads? They are a replacement item at certain service intervals.

Another option for an engine swap is a head swap. The KA24E head can apparently fit onto the Z block, with some minor adjustment, and you'll end up with a slightly higher compression plus fuel injection set up. Another advantage is the KA24E is either 12 or 16 valves, not 8 like the Z. Better fuel efficiency and power

 

[Tappet]

I wouldn't shave the head not in that old girl. It will up the combustion pressure and blow by will follow.
If your running rough is a more of a miss than a surge you could be looking somthing mechanical or electrical. If it doesn't idle/cruise clean (steady) it's more likely the fuel side of things.

Consider having a quick 4 gas exhaust analasis it can tell alot, if the mechanic or you you know what your looking at on the screen. Get them to quickly hook it up to an old style scope and they should be onto what ever is going wrong in minutes.