Rebuilt engine 318 Question

My 318 overheated and i blew two of the pistons

Pretty much a lot of money is going to be put into rebuilding that engine


So i thought i would just buy a rebuilt one already, But i have never done this and i was wondering if anyone has ever done this or if anyone has any opinions when purchasing from Ebay or a website

I have a few links you guys can check out
------------------------------------------------------------------------
http://cgi.ebay.com/ebaymotors/DODG...tQ5fPartsQ5fAccessoriesQ5fGear#ht_3676wt_1165
------------------------------------------------------------------------
http://cgi.ebay.com/ebaymotors/DODG...Q5fTruckQ5fPartsQ5fAccessories#ht_3883wt_1165
----------------------------------------------------------------------
http://www.precisionengine.com/rebuilt-engines/dodge-mopar/index.html
----------------------------------------------------------------------
its a 318 5.2 V8 Mopar for a 1974 Plymouth duster


Also kind of wondering if i would have to rebuild the transmission if im getting a rebuilt motor


Thanks guys for any help, i am very limited to my knowledge of cars, and i am still always learning so much.