dart custom 318 headers?

SinSled, the problem with headers and MoPars is that pretty much for the last, oh, many years since headers were made, few people have cared less to make a actual street header for the small block cars. The header companies came up with a design that was copied by everyone else.

The one size fits all design has 3 tubes that run under the drivers steering linkages. This makes installation a pain since you must disassemble the linkage and run it through the header. The big draw back is the tubes hang very low for street use. It is now only a matter of time before the tubes hot road debrise and get dented &/or flattened out.

Enter a couple of companies that actually did something to address this issue.
Doug's and tti. Both are pricey.
Doug's headers are a little more compact. Tube size is 1-5/8. This works very well for 90% of the street & street strip cars on the road.

Tti headers are a stepped header. There 1-5/8 tube goes up in size after a few inches off the head to 1-3/4. Tti also makes full exhaust systems for the car as well. From header to tail pipe. With and without mufflers. IIRC, they offer DynoMax mufflers with there systems.

Both headers are expensive by compare over the 1 size fits all headers. But you won't bash your headers on the road wrecking what you paid for.