IF you are going to use the Hooker Supercompetion long tube semi fenderwell headers ( and I have them in a 65 Valiant Signet), DO NOT follow their exact cutting instructions!!!. Cut smaller dimensions first, then expand to allow for your install. If you follow hookers instructions you will cut out your upper shock support on the drivers side. I use aluminum plates to cover up the size of the hole you have to make to get them in there. And the drivers side is 4 pieces , so sealing the slip joints winds up being soooo much fun. HAve them ceramic coated first.. the heat is nuts without it ( you know how I already know that). Your tires may rub slightly on tight turns on the tubes inside the wheelwell.
I have removed and reinstalled mine 4 times in the last 10 years. The last time to have them ceramic coated.
Patience will be your friend.. It is an extremely tight fit but it does work.. Now I have an automatic, so someone else can chime in on doing it with a standard in the early A.
And they make the car sound and run great!! Search for my "10 year refresh" post and you can see the holes I cut in the fenders.