| Intake manifold runner flow testing |
| Edelbrock performer intake maximum runner flow as cast center runners: 275 cfm with carb pad clay radius. Outer runners 250 cfm with carb pad clay radius . #1 runner on Std port ported D0VE-C 350 cfm port: 250 cfm @ .800" lift with carb pad radius. #1 runner on CJ port matched D0VE-C 261 cfm w / carb pad radius #1 runner on CJ straight entry port match w / 850 DP 250 cfm @ .800" lift |
| Weiand "Stealth" CJ port STD carb pad maximum runner flow as cast Short and long runners with clay radius on carb pad 340 cfm Runner #1 with 750 DP 305 cfm Runner #1 with 850 DP 320 cfm Runner #1 on std port D0VE-C (340 cfm max) w / 750 DP 251 cfm @ .800" lift Runner #1 on CJ port match angled entry w / 750 DP 277 cfm @ .800" lift Runner #1 on angled entry CJ port match with clay radius / carb pad 325 cfm Runner #1 on straight entry CJ port match with clay radius / carb pad 340 cfm Runner #1 on straight entry CJ port match w / 750 DP 287 cfm w / 850 DP 301 cfm |
| Edelbrock Victor 2966 maximum runner flow as cast Long runner #1 with radius on carb pad 355 cfm short runner #6 with radius on carb pad 365 cfm Long runner #1 on straight entry CJ port match (387 cfm max) with radius on carb pad 355 cfm Long runner #1 on same head with 850 DP 343 cfm Long runner same head with 750 DP 329 cfm |
| More flow checks coming |
| By virtue of its access to the entire plenum the single plane victors smaller runners outflow the CJ stealth's larger runners. This is due to the dual planes runners having access to only 1/2 of the carburetor. The oval shape of the carb pad is actually about the same cross section as the CJ runner but the flow has to make an abrupt turn as it traverses to the runner. Carburetor size has a dramatic impact on runner flow. A carb of 850 cfm and larger offers little resistance to flow on my bench. The bench will literally pull the vacuum secondarys open on my selection of holley carburetors. Also of note is the fact that port entry shape has a good bearing on intake tract flow overall. When the first 3/4" of the CJ port matched port is straightened, flow is enhanced by 10 to 15 cfm over all. This was true on all manifolds tested so far, even the std port performer. The symetrical port layout of the BBF causes some difficulties with runner exit to port entry airflow path alignment. The flow path has to change direction and this change causes a flow column velocity / energy loss. This is especially true of cylinders #4 and #5. There are subtle differences in these intake ports as cast to help off set this phenomenon. These 2 cylinders suffer from fuel falling out of suspension because of this. |
| Runner flow in this chart is at .800" lift |
| The formula (.25714 x runner flow) x number of cylinders will give you an approximation of HP. potential for a given flow in cfm. This formula assumes an optimized max effort application. |
| Further testing has shown that when ported the victor runners will flow in excess of 400 CFM and 360 or better when attached to a SCJ aluminum casting. These flow numbers will support high RPM flow and HP. |