4.0 ohv mods

[rmitt]

im looking to build a 4.0 ohv semi conservative and swap it out with the existing motor. i was wondering what mods are worth it and what isnt. i plan on rebuilding the whole thing keeping the bottom end stock.
any help would be great

 

[nitrofan1]

Welcome to TRS! If you are sticking with the top end start with a more aggressive camshaft. Are you looking at a port & polish?

 

[rmitt]

thanks! definately, but sould i buy aftermarket heads or stick with stock ones?