You should look into getting 5.9 magnum exhaust manifolds with a small section of tail pipe, flange & bolts. They will most likely flow better than stock 273 manifolds. you will have to trim a few inches off the lower steering column. this option will only work with manual steering. AS said above 650 cfm great for street ca
Looked into it, decided not to. At the end of the day I'm making more than enough power for what this thing is. Also playing dress up as a 273 is kinda appealing. In this 64 dart magnum exhaust is a tight fit.