When I bought the car it had a set of regular Hedman Long Tube headers that were thermally wrapped to help manage the heat. I looked into coating them, but later decided to buy the exact same headers brand new and already coated. I bought my Hedman Elite long tube headers (P/N 88308) from Summit Racing. Click here to see them at SummitRacing.com. They have gone up about $20 or so since I bought mine 3 years ago, but they are still a great value.
The headers feature 1 5/8" pipes with 3" collectors. The fit is perfect, but as with any long tube header you will need a power steering drop bracket to clear the bottom of the brackets if your classic has the factory power steering. These are basically the same as the Hedman 88300 headers with the exception of the thicker 3/8" flange, the coating, and the badging. I almost didn't buy these because many people were saying to be cautious of factory-coated headers. I have had mine for 3+ years and have not had a single issue with the coating changing color or coming off.
I am not going to give a rundown of how to install headers, as this is a fairly obvious process. However, the main thing I would recommend when installing coated headers is to wrap them with some thin protectant when maneuvering them into place in the car. A buddy had his done and complained about scratching them while putting them in the car. My solution was to wrap my headers with thin packing foam sheets (see Fig 3 for an example) — there was some in the box that my headers were shipped in. The great part is that it is very thin, bends easily to conform to any shape, and once you get the headers positioned in the car it is easily torn off.
I am not sure where I read this, but somewhere along the way I read that the headers should be cleaned using steel wool. This works surprisingly well to take off any types of road or oil stains that will ultimately happen if you drive your car regularly.
