It is interesting to see the variety of flow numbers that people get from SBF heads. Found a chart online that listed results from a variety of manufactures.
https://www.google.com/url?sa=t&rct=...1SqRFtb-QkdRfS
The results vary significantly from a stock 289 head at 166 cfm Intake (.600) and 125 cfm Exhaust (.600) to a Kasse SVO head at 374 cfm Intake (.600) and 273 cfm Exhaust (.600).
When I was discussing my heads with the engine builder at Cobra Automotive he was saying that their ported race heads are producing over 300 cfm at .700 intake. Heard from several people that my heads in their old form with flowing about 260 cfm at .700 were the limiting factor in my engine. In addition, you have to factor in the carburetor's flow capacity, as while the head might be able to flow a certain cfm, a restrictive carb system will have an impact and the head can only flow what the carb provides.
I have settled on getting cam options from three sources based upon my discussions with them. They are Brent, Cobra Automotive and Shelby Racing Engines. Dema Elgin supplies the cams for Shelby.
Should be able to make a decision soon, as I need to get this engine together.
Jim