source for 4.6 motors?

anyone here know of a good source for 4.6 mod motors, either crate motors or kits? I need to replace or rebuild the motor in my '92 CV and would like to upgrade it to 99-02 GT spec, maybe even a little hotter. any help would be greatly appreciated.

Does anyone know how low cost mods such as porting affect the 4.6 SOHC motor especially the later versions. I have only found one source for aftermarket valves and a few for cams. Both mods are very expensive. Would like to know how effective a do it yourself port and polish would be.

Sean Hyland and Steeda are dominant in the 4.6 aftermarket.
For used motors, try stangparts.com