Be very careful on your decision making when it comes to buying used race parts
I have used a bunch of different heads on my race cars over the years from stock iron 516 on street motors to NHRA legal stock 1963 M.W. heads on my old NHRA A/SA Plymouth Belvedere to Indy 440-1 on bracket motors.
My current bracket S/P car has a set of used Victor M.W. heads on my 505 C.I. 400 block, I raced that motor with a set of Eddy RPM heads that I had MCH CNC port them and then switch the M.W. Victors that winter, mine where M.W. ported all the way to the seats, not like Edlebrock said they sold them out of the box originally I wouldn't buy another set of them regardless of price
Buy the good ones once, don't repeat my mistakes on trying to save money by buying and using used race parts , especially heads