dbane261,
I believe that you have studied the May 1955 HRM article about Frank McGurk's 261. Looking at the dyno test results from McGurk's 261 in 1955, the combined effect of increasing compression ratio from 6.75 to 7.85 and porting was to increase HP by about 2% at 2000 rpm, 7% at 4000 rpm, and 16% at 5000 rpm. The textbook equations indicate that the compression ratio change alone should increase HP by about 4% at all speeds. This would then say that the porting reduced HP by 2% at 2000 rpm, broke even at 2300 rpm, increased HP by 3% at 4000 rpm, and at 5000 rpm (if one wants to go there) there would be a 12% increase in HP. Are these changes worth it for a daily driver? Will a more modern approach to porting show better results? Let us know the results of your build.
Good to hear that your potential oil pump problems may be solved. Best wishes for your endeavor.
Last edited by Hoyt; 04/15/09 11:34 PM.
