[Stan Weiss]

Originally Posted by slowbird

My HP heads kept getting larger and hp and rpm kept increasing. CFM never really picked up much. In my case larger was better.

Port velocity on a flow bench is one thing, and on a running engine is something else. While everyone talks about cfm for a give engine size, RPM and VE% you also need to have correct CSA.

Stan
.

[Jay S]

Pulled some stuff from your date base Stan, curious if there are patterns.

Is the KRE high port correct? Anyone have port cc numbers after porting like Slowbird mentioned? The higher port entry must effecting that one.

CFM per port volume

Stock D port Iron
211 cfm 146 cc. 1.445 cfm/cc
153cc. 1.39 cfm/cc
Jim Hand 64s
253 cfm. 165 cc. 1.533 cfm/cc
Jim Hand 6X-4
268 cfm 170 cc 1.57 cfm/cc
614 RA 4. Production
231 cfm 182 cc. 1.17 cfm/cc
614 RA4 bowl porting
252 cfm. 186 cc 1.354 cfm/cc
197 455 HO, deep 60* valve cut
243 cfm. 174 cc. 1.396 cfm/cc
6X 2.125” ported
292 cfm. 196cc. 1.48 cfm/cc
Edelbrock round port 72cc
282 cfm 215cc. 1.31
Edelbrock. STEVE C
317 cfm 227 cc. 1.396
Edelbrock SD performance 2.19 race
333cfm. 235 cc. 1.428
Edelbrock D port
272cfm 185cc.HHP. 1.47
KRE D port Jim Hand
273 cfm. 186cc. 1.47
KRE D port 295 CNC
290 cfm 197 cc. 1.47
Edelbrock Wide Port 2.18
375 cfm. 255 cc. 1.47
KRE High Port OTB w/valve job 2.20”
330 cfm. 277cc. 1.19