hi all..does anyone know what the physical differences are between the 66 & 67 390 h pipe? i see the 67 for sale often but never the 66. i know the left manifold was redesigned for the mustang cougar, but what is the actual difference between the pipes and can it be easily modified? thanks for any info. dwight

the angle of one or both exhaust manifolds. I contacted Waldron's Exhaust and ask the same question. The reply said that 1966 390 Fairlane H-pipe was a one year only part. They didn't elaborate on the exact difference. It is possible to make a 67 fit (I have heard) but I don't know what is required. Big hammer and big arms probably. Scott66gta used Waldron's and said they made a perfect fit for his 1966 GTA. Price was $280 (I think) for the H-pipe and about 3 weeks to manufacture it. It was around $600 for a complete exhaust system. I think I must have deleted their e-mail. I couldn't find it. Here's the link to them http://www.waldronexhaust.com/
Good Luck and let us know what you do. If a 67 fits, they are cheaper and more available. I see them on Ebay all the time.
Murfman66