Did you really grind 20+ cc out of an 062 casting head?
Where in the port did you take that much out?
Have they been on a flow bench, or is that 280-290 cfm estimated?
Will this engine see a dyno?
Right now the heads are "in process" as I get a break from other work, so I hit them a little bit here and there. The heads are right around the 182-183cc mark right now and the flow is in the 270's at .550 lift with a small throat and still using the 1.94 valve and seat diameter. The Pushrod Pinch is in the 2.2" area and the short wall is pretty straight but a good 1/8" from the bolt hole. The last thing I worked with was the S.T. to keep the air attached, next I am going to get a 2.02 valve in there and finalize the throat/bowl area as that is faster than I would like it.
So no, I have not finished the port, but with the sonic tester I have room to work where I want to. It seems the thinnest spot on the heads are the short turn. But with larger valve area and correct throat and seat designs I should be able to easily get the port into the 280 range and "maybe" 290.
I have done several sets of the old 185cc GMPP Vortec heads ported to 200cc and 2.00 vavle they would go close to 300cfm at .600 or .650 lift. So I should be able to get these pretty close.
Also note these are my personal heads so I can afford to take extra time to really tweak on them, my limiting fastor is going to be the intake flow attached to the head, I may stop short of the extra flow if the intake seems to restrict it too much and I can't pick it up.
Is it cost effective to do this, probably not but I have the castings and not in a huge hurry to get the motor done.
The motor will not go on a dyno, but track testing will be done. I am willing to put an automatic and correct converter in the car if the Muncie can't handle the power. This is all going in my personal '65 Chevelle street car.