For Sale: A Pair of 990 Cylinder Heads. $500 (located in Rancho Cucamonga, CA)
These should be gone through, but came off a running 454 jet boat motor.
Here's more info and pics...
Dual Springs set up for flat tappet camshaft (were used with .542 lift cam.)
Stainless Steel Severe Duty Manley valves (2.19, 1.88)