grumpyvette
Well-known member
read this, BUT keep in mind it does little good to have killer head flow numbers if the intake manifold flows less or if the exhaust is restricting flow, and heads that flow killer numbers at .700 lift, and are designed to feed a 427 displacement at 7500rpm, DON,T do you much good if the CAM you sellected has a .520 lift AND ONLY SPIN THE ENGINE TO 6000RPM
http://www.tmossporting.com/tabid/1805/Default.aspx
BTW.
ITS A COMON MISCONCEPTION,THAT YOU MEASURE PORT CROSS SECTION AT THE PORT ENTERANCE,BUT ITS NOT the port area at the enterance , you need to use in the calcs, ITS the MINIMAL port cross section at the SMALLEST point in the port, usually near the pushrod area.
LIKE a funnel, its not the largest part of the opening but the smallest thats the restriction to flow
SO HOW do you MEASURE THEN??
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5649
http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-900014&N=700+115&autoview=sku
USE THIS
http://www.rbracing-rsr.com/runnertorquecalc.html
http://users.erols.com/srweiss/tablehdc.htm
http://www.malcams.com/legacy/misc/headflow.htm
here’s a chart FROM THE BOOK,HOW TO BUILD BIG-INCH CHEVY SMALL BLOCKS with some common cross sectional port sizes
(measured at the smallest part of the ports)
...........................sq inches........port cc
edelbrock performer rpm ....1.43.............170
vortec......................1.66.............170
tfs195......................1.93.............195
afr 180.....................1.93.............180
afr 195.....................1.98.............195
afr 210.....................2.05.............210
dart pro 200................2.06.............200
dart pro 215................2.14.............215
brodix track 1 .............2.30.............221
dart pro 1 230..............2.40.............230
edelbrock 23 high port .....2.53.............238
edelbrock 18 deg............2.71.............266
tfs 18 deg..................2.80.............250
Potential HP based on Airflow (Hot Rod, Jun '99, p74):
Airflow at 28" of water x 0.257 x number of cylinders = potential HP
or required airflow based on HP:
HP / 0.257 / cylinders = required airflow
http://www.tmossporting.com/tabid/1805/Default.aspx
BTW.
ITS A COMON MISCONCEPTION,THAT YOU MEASURE PORT CROSS SECTION AT THE PORT ENTERANCE,BUT ITS NOT the port area at the enterance , you need to use in the calcs, ITS the MINIMAL port cross section at the SMALLEST point in the port, usually near the pushrod area.
LIKE a funnel, its not the largest part of the opening but the smallest thats the restriction to flow
SO HOW do you MEASURE THEN??
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5649
http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-900014&N=700+115&autoview=sku
USE THIS
http://www.rbracing-rsr.com/runnertorquecalc.html
http://users.erols.com/srweiss/tablehdc.htm
http://www.malcams.com/legacy/misc/headflow.htm
here’s a chart FROM THE BOOK,HOW TO BUILD BIG-INCH CHEVY SMALL BLOCKS with some common cross sectional port sizes
(measured at the smallest part of the ports)
...........................sq inches........port cc
edelbrock performer rpm ....1.43.............170
vortec......................1.66.............170
tfs195......................1.93.............195
afr 180.....................1.93.............180
afr 195.....................1.98.............195
afr 210.....................2.05.............210
dart pro 200................2.06.............200
dart pro 215................2.14.............215
brodix track 1 .............2.30.............221
dart pro 1 230..............2.40.............230
edelbrock 23 high port .....2.53.............238
edelbrock 18 deg............2.71.............266
tfs 18 deg..................2.80.............250
Potential HP based on Airflow (Hot Rod, Jun '99, p74):
Airflow at 28" of water x 0.257 x number of cylinders = potential HP
or required airflow based on HP:
HP / 0.257 / cylinders = required airflow
