Tight fit to get exhaust pipe into

If you are looking for a direct fit, TTI makes head pipes specifically for this application. I am swapping my headers for manifolds and plan on going this route on my Scamp. I used their complete exhaust system on a 74 Duster years ago with 340 hi po manifolds and it fit perfectly (manifolds back system with head pipes, H-pipe, dynomax mufflers, tail pipes and SS exhaust tips)