...My experience has been that trying to completely remove the humps in the roof by the head bolts is worth almost nothing unless it's a truly MAX effort deal...
Yeah...certainly this is NOT one of these MAX effort situations...only looking for easy improvements. As-is, here are the port flow numbers off of a SF-600 bench:
LIFT I E
0.100 67 57
0.150 99 79
0.200 130 104
0.250 162 125
0.300 189 140
0.350 215 152
0.400 235 160
0.450 253 167
0.500 262 172
0.550 261 175
0.600 248 177
...I find it fairly difficult to get these heads to not start to back up(turbulence) at much over .500 lift, if you've got the rest of the port opened up to allow a noticeable increase in airflow(say around 240cfm and up).
So I think I saw precisely that behaviour with my heads...the flow numbers started dropping off right at the .550" mark.
...What I often do is use 2.055/1.625 SBC valves, which provides a nice flow increase in the area under curve, although it doesn't help with the ports backing up at high lifts...
If I was re-doing this, yes, I would probably go with a 2.05" valve, but for now, it stays as-is. No more money to sink into these casting...I am saving up for the W2 Econo heads next...LOL.
