Get yourself a Jeg's catalog.
For a step up you may want to consider one of the following heads, all found at Jeg's:
Roush 200 cast iron: 200cc intake, 64cc combustion chamber, 2.02/1.600" valves = $399.99 each, assembled.
World Windsor Jr 180 cast iron: 180 cc intake runners, 58 cc combustion chambers, 1.94/1.600" valves = $397.99 each, assembled.
I run the Windsor Jr's and love them. I believe Summit carries the Roush heads. I know they carry the Windsor Jr. heads because that's where I bought mine. Try their website to compare prices.