moturbopar
Well-Known Member
Hey all Im messing with some 915 closed chamber heads. I have not ported these before, seem to respond differently than 906 heads.
Really need to knock back the short side to pick up flow, and the guide boss is huge!!! Anyways the heads have been opened up to 2.14 1.81 valves. Good 3 angle valve job. when I checked flow before any work The port maxed at 219 cfm at .050 picked up a lot with cleaning up the extra metal left from going larger valves went to 239 cfm at .050
Anyways after cutting back the short side, and narrowing the guide, and opening up the pushrod pinch. .080 it seems to have picked up nicely. The problem is the head maxes at .525, starts falling off above that. The head is a street head that will only see .512 lift. I think the head should be a great street head as is.
intake CFM numbers rounded to nearest whole
.100 78
.200 148
.300 204
.400 247
.500 259
.525 274
.550 265
Really need to knock back the short side to pick up flow, and the guide boss is huge!!! Anyways the heads have been opened up to 2.14 1.81 valves. Good 3 angle valve job. when I checked flow before any work The port maxed at 219 cfm at .050 picked up a lot with cleaning up the extra metal left from going larger valves went to 239 cfm at .050
Anyways after cutting back the short side, and narrowing the guide, and opening up the pushrod pinch. .080 it seems to have picked up nicely. The problem is the head maxes at .525, starts falling off above that. The head is a street head that will only see .512 lift. I think the head should be a great street head as is.
intake CFM numbers rounded to nearest whole
.100 78
.200 148
.300 204
.400 247
.500 259
.525 274
.550 265
