Changing out 318 to 340 on 73 Dart Swinger

It all depends on what rear end your 73 dart came with to withstand the 340. If it has an 8.25 rear should be fine but a 7.25 will not last long at 400hp. Dustin
Thanks so much. I will get specifics on the drivetrain. And the auto tranny should be fine? If I buy a solid 73 right, is it a good idea to put a 340 in it and try to muscle it up.. some Mopar buds act like nothing good was built in 73.. your views?