Home ported small block heads.....

I decided to try and port a slant head about 11 yrs ago, i played it safe and netted about 20 cfm over stock flow. I really got into porting about 8 yrs ago on a set of x heads, after removing the kink in the bowls roof just off the guide and a lil laying back of the turn and bowl enlarging just off the seat...they went 242 cfm on the int, on the exhaust i polished the entire port and worked the tall side of the turn at the wall trying to exaggerate it more 'like it had more short turn' and netted 192 or so cfm. i believe i posted the flow sheet on this site already.
I also went to town on a set of '71 j heads with 11/32 stem 2.02 /1.60 valves and netted 270@.500 int first shot with 190's exhaust flow.
The thkngs i did were cutting the guide narrow and shortining it, working the straight/dividing wall, raising the roof, opening the bowl up big time and widening the short turn as much as i?felt comfortable with 'at the time', on the exhaust i did the same exaggerating of the tall side at the wall, opening the bowl up and going straight up from the seat with a lil roundness at the top of the turn at the floor, then grinding the kink out of the roof and working the walls to an even cross diameter from the bowl out making sure not to end up bigger at the port window 'slows velocity if too big'. I found with the addituon of a flow bench that i could olay around with the chamber shrounding and chamber side angles off the seat and load the seat in different areas, so if i played with too much unshrouding at the short side especially at the bore/close to chamber side...that all the air would want to go there and if not more than the total flow 'pre existing' would become a wall and cause turbulence giving -less flow...
factory casting in the right hands will flow as much as most of the bolt on after market performance offerings...and sometimes even more in the low lift range and with the right piston can be more practical/helpful on a street motor/street lift range for power. im typing on my phone, sorry for my engrish.