340 X heads
As stated before unless it's for a numbers matching car, need for a period correct racing like that FAST crap, do yourself a favor and get aftermarket heads either w2 Eddys or RHS will do you much flbetter in flow and money spent. Example I spent $200 buck less to have my x heads rebuilt. But if you include the cost to buy the heads it was more like $50. I'd have been better off getting a set of Eddys like I have now (though before I went with the Eddys I kept trying to find a good set of w5 heads but not luck, sure enough 3 months after I got the Eddys a set of w5 with late model casting came up for sell).