A lot of money. This working on iron is a pain in the butt.
Send us a set of clean good cores and we will install thick wall bronze guides, valves, port, clean mill the combustion chamber side, and cc the heads, 285-290 cfm $1550. You looking for 300 cfm $1750. Anything else is an additional cost. Milling, springs, retainers, locks, seals, hard seats, blah, blah, blah....additional.
