2 types of Doug headers for early 64 to 66 Valiants ??

In the early 70s I acquired a 1965 Barracuda that had been an SCCA A-Sedan racer since new and had a history in the overlaid "Pro" Trans Am series. Of a few exotic components and mods it had a set of full length under-chassis headers made by Doug Thorley. The company has gone through permutations of "Doug's" and "Thorley" and so forth since the 60's and I have not tracked or kept up. But I can say that the race car set I had were a nightmare for my street adaptation. The bellhousing was a beefy stamped scattershield and the driver's side header consisted of a section installed from underneath with two upper tubes inserted separately down from the ports above. Clearances around the steering linkage and starter were fractions of an inch. Street driving stressed the starter to the extent restarting when hot would often fail for the baked starter. In the day of being able to buy sheet asbestos I fabricated an aluminum plate and asbestos sandwich shield that helped but didn't totally mitigate hot start. I know my experience isn't wholly relevant to current product advice but I have one comment resulting from my 50 yr old episode. I have built a number of hot motor early A-bodies since and have concluded that you can't go wrong with a set of factory 340 manifolds. I came to conclude that the theoretical performance advantage of full length tubular headers isn't worth the fitment brain damage. One of my most satisfying and seat of the pants fastest variations used iron manifolds. There are lots of other engine tuning variables that will kick *** without needing sheetmetal pipes.