The cam is a little more aggressive in the stock 4.2 compared to the stock 3.8 cam.
It depends on which parts you are talking about. The 01+ 3.8 parts are better for the 4.2L swap for the most part though(excep the lower intake with the IMRC's).
You can also get a 97-99 4.2 FYI.

 

okay so ill get the 99-04 4.2L because i want the newest i can get....and ill get the block, crank and cam
ill use 01-04 mustang parts

what should i use for the lower intake thenn????

 

So you are going to keep the stock cam? If you are going to have the motor apart you might as well put in a better cam. The 01+ have IMRC's in the lower intake, which can be tricky to tune around. Your stock 2000 lower dosn't have them, so that would be ideal to use. I would also port that, the 4.2L's love to breath.

 

well i plan i getting the best in whatever i put on....i wanna build the motor to produce the most power and best performance....any suggestions on a cam? also im not pulling my motor and using parts from it im building accordingly buying new parts or machineng others.......what does ported mean i have some idea but not 100% sure

 

i would say a 212/218 cam would do you just fine

 

where is a good place to get the parts from....i usaally get a lot of my parts from mustangs unlimted but thats just becuase im close to it. Also i really dont think they will have the parts neccassary to support what i need.

 

www.supersixmotorsports.com will have most everything you will need.
Ahhh. Ok, well now the question is are you building it for N/A(no turbo, supercharger, or nitrous) or F/I(turbo, supercharger or nitrous)? Are you wanting to run pump gas in the motor or race fuel?
Ported = porting = the widening of passageways so it can flow better and push more volume through.

 

i would be buliding it F/I....and i would want to use pump gass.......


Is it possible to just do a 5.0 swapp cuz my freind has a motor hes selling and he thinks it will workk??

 

I guess, I don't really know much about motor swaps.

 

yea nnever mind the 5.0 wont work.....thats a good website for the 4.2 parts i feel more confidant in doing this now knoing that that site has basically evrything