Almost all the flow in a FE exhaust port is in the upper, outside 1/3 part of the port. If you start the contour of the exhaust back in the port and turn it down like the factory tried to do, you can help the flow increase. Check out a GT-40 iron head on the exhaust side. The new CHI heads turn the flow in almost a 180* turn down out of the port from the valve. If you could keep the lower part of the FE exhaust floor in a curve parallel with the roof, it would increase flow. What works on some heads is to bias the flow out the side of the port instead of the roof. It takes work, but can be done with patience and bench testing. A Pond head is a prime example of no short turn on the exhaust, but the port can be made to flow 250cfm by tricking it out sideways. Joe-JDC.