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| The intake bowl polished up nicely. | |
My goal was around 300 cfm at peak and a nice fat curve. We’ll get it there. So far, all I have done is gasket match the intake port entrance to a FelPro #1262 gasket and blend with a sanding roll the rest of the runner and bowl area. I now have 228.3 cfm @ .400” lift and a whopping 290.10 cfm @ .700”! That is a 26-cfm gain at .700” lift with only minor port work! I am going to try to achieve 300 cfm peak without ruining the mid-lift numbers and without any fancy port work.
 The finished exhaust bowl. |
I am also going to leave the factory multi-angle valve job alone. The intake seat has a 4-angle configuration and the exhaust has a 3-angle seat into a full radius bottom cut. Pretty sweet for the money.
Next issue I will publish the complete before and after flow charts and show a few more “tricks” to boot. As for the exhaust, I’m home free baby! The as-cast numbers at .400” lift and .700” lift were 161.10 and 181.7 cfm. After matching the port exit to a SCE copper
gasket on the top only and blending the rest with a sanding roll, we now have 162.4cfm @ .400” lift and 201.60 cfm @.700”!
Trust me, everything I have done so far is possible for anyone to duplicate with a little patience and control. These heads are going to work out just fine for a 347-cube engine. I am shooting for a peak power rpm of 7500. I purposely went for the 200-cc runner heads as opposed to a 180-cc runner because I want to kill a little bottom end torque for this monster and hook up the 9 inch wide slicks. Not that it will be a dog on the bottom end, quite the contrary. I just want to move the rpm range up as high as practical.
Next month I will finish the heads and move on to the rotating assembly. This is going to be a fun project and I hope you will find something useful along the way.
Remember, there is always hope. When in doubt. . .DO A WHEELIE!!
