is this exhaust ok

what i have done to my car was reverse the manifold and attached a 4" copper pipe 3/4" thick, what are the disadvantages of it?
here is a pic..no real just did it on ms paint

the engine i got in there is an 18ss


http://files.automotiveforums.com/g...php?photo=46587


that is pic..

u can reply with technical terms, i am not a noob :D

The link doesnt work

sorry here u go

www.trip2trance.deltaverse.com/tc3homemade.jpg

thats too long. you'll lose pressure