below is from an article in Hemming Motor News. I bought the Flaming River and it was a direct bolt-in, no header issues (TTI 2" primaries) and is really nice, also cut atleast 10lbs off the front of my car. Best price I found was Speedway. Did not need a ptiman arm.
For the most part, Mopar power steering gearboxes from 1966-'74 only came from the factory in a 15.7:1 ratio and 3½ turns of the wheel, lock to lock. Manual boxes were built with a 20:1 ratio. The only Mopars with a quicker ratio gearbox were 1970-'71 AAR and T/A models, and your chances of finding a replacement unit from one of these cars are almost nonexistent.
Don't give up, though: Using the conventional 15.7:1 ratio power steering box with an extended Pitman arm and idler arm can attain a similar improvement in the car's handling.
You can get these extended-length components from Firm Feel Suspension. Parts are available for all popular A-, B-, C-, E- and F-bodies. The added length effectively adds to the response of the steering system, serving a similar purpose to modifying your existing gearbox. Earlier Dart and Valiant A-bodies (1964-'72) using these extended length steering components also have to change to a later 1973-'76 A-body center link to maintain the correct steering angles and clearances.
Firm Feel also remanufactures Mopar steering boxes to three different levels of firmness, depending on your models specific needs. The Stage One is similar to an original police car power steering gearbox. Stage Two units will cover most street car and muscle applications. The firmest units are Stage Three, which Firm Feel claims to be the heaviest unit for Mopar applications currently being built. These Firm Feel units sell for about $350 with a rebuildable trade-in unit exchanged. Rebuilt units come with a one-year warranty.
Flaming River produces a replacement manual steering box for Mopar muscle applications. This is a direct bolt-in unit, which replaces the original 20:1 ratio with a quicker 16:1 ratio box. The Flaming River unit is brand new and requires no trade-in.
