4A-GE MK1 Engine large port head

4A-GE MK1 Engine, port, compression, head, engine, difference, 115hp, ratio, milling, sounds, shape, good, 10.5-1, block, stock, rebuild, performance, mild, wondering, heads, cylinder, large, milled, safely, design

im doing a mild performance rebuild of my stock 85 engine and i was wondering how much can be safely milled off the cylinder heads. seems other than port design compression is the difference between 115hp in my engine and 140 in the red top. id like to get around 10.5-1 compression ratio and my block is in really good shape so milling the head sounds like the way to go.