How big of valves can I fit in stock heads?

[Stang Runner]

I have ported the stock heads And I might put larger Valves in it, How big can I go and How much for it. I am going to a shop Wed. I went to the shop and the guy went home all ready. Would it be Under $1,000???? That is all I will go could can I get any thing done foe that??

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14.28@103.0 on a G-Tech Engine: Steal Mounts, Under drive pulleys, K&N, Home ported Lower Intake, No power steering, No A/C
Drive Train: 3.55, World Class T-5,
NOW it is time for Real power STUFF I Have and will put on after I get everthing: Mac cold intake, 70MM TB, Valve covers (COOL ONES)255 Fuel pump NOS Dry 75HP.
Next to get: Rocker Arms,Cam,TFS Heads,Injectors 24,Holley Intake, What might I need???See It at <A HREF="http://www.computerconquest.com" TARGET=_blank>www.computerconq