I finally got the head back for my 80 aspen. All of the exh seats were pitted and the exh valves had to be replaced. The seats were given a multiangle cut and a lot of excess casting was removed above the seats in the bowl area. The ports were untouched. It was given a 0.062 cut and the chambers were relieved next to the exh valves. All of the chambers initially cc'd at 54. I put the heads back on with ARP studs. I also gasket matched the exhausts on the manifold. The engine was built OEM using a steel shim head gasket. I used a FelPro composite. Compression should now be around 9.25:1. The car runs great! One thing I noticed is the engine now pulls higher vacuum for the same driving indicating it is running more efficiently. While I had the carb off, I removed the plug for the power valve channel restriction and drilled the restriction from 0.036 to 0.043 for about 12% more fuel under power. What fun it is to drive this car now.

The fellow who built the head is very experienced. He told me the depth of the hardening in the seats is much greater than usual.

Mitch

It is nice when a project comes together well.
Time for a little "tuning and tweaking" to get this combo running "razor sharp"!
DD

The green arrow points to restriction, small brass. Have measured two different carbs different sizes each carb one was about .033 the other one was point .051

Man, you replied to a thread almost 18 years old.

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Joshua

It's an old thread, but it could be just the thread I needed for the problem I'm having (ping at WOT, most likely due to leanout). Maybe instead of changing carbs I can "fix" the one I have.

By 1976 both of those power valve systems previously posted we're gone replaced by a new system. Except for heavy duty emissions trucks which maintained the throttle modulated power valve. After a certain throttle opening was reached the vacuum supply to the power valve was dump to atmosphere. The California throttle modulator system apparently didn't work out either probably required real good throttle adjustment.