I don't think you'd find many performance head shops to refurbish an old set of iron heads, install all new performance oriented parts, and port them....... For anywhere near what you can buy a set of E-Street heads for.

About the only time I do iron heads anymore is for resto type builds, or where the rules require it.

IMO, the cores only have any value at all if they aren't cracked....... Which is often pretty hard to know until they're cleaned and magged(about $100).

Cleaned, magged cores that check out good are probably worth $150-200...... To someone that really has to have a set.

Unknown cores? $40 max IMO........knowing you're taking a gamble on them.