Exhaust Manifold Application Question

You may need the 90 adapter for exhaust clearance I know it is required if you use the HP 340 manifolds. Generally cars that came with duals used them. I had duals put on my 73 Dart with a 318 and those manifolds and there is filter clearance but it is tight. I run the 16 filter instead of the 43 gives about another 1/2 of clearance. If your having the exhaust bent up from scratch i think a good shop will get you buy without an adapter. If your going to run larger pipe for future upgrades and reduce it to fit the manifolds you may need the adapter.