I think it depends on how much money you want to spend, and how much power you want to make. If money is no object, you have a lot of options. Have the plenum cut/milled off and have the head ported/polished. You will then need an aftermarket intake, like one offered by zzfab and others. Heavy duty springs and pushrods. If your head has pressed in valve seats, you run the risk of dropping a seat with high rpm's and or high egt's. Last fall I dropped two seats while racing. To fix that I bought seats that are harder than the stock seats, and rated for higher temps. I also had them recessed for more clearance. To take advantage of a nicely setup head you will need an aftermarket cam. There is a lot of reading on here about this subject to help you make good decisions on what to do, and who's products to use.