I think I can get the 5" down under the front of the engine and split it to 2.5-3 down the passenger side of the engine without to much problems. Cuda has 2.5 right now out the back thru series 40 flowmasters and original square tips. I do however have a 3.5" setup with Race Bullet mufflers too. I may need to cut the passenger side inner fender and run it out there and over the front tire. Then I could route it back thru the inner fender where you would cut for a fenderwell header setup and drop it right beside the engine/bellhousing. I will have to wait for the 400 and get it in the engine bay to determine how this will be done.