Baker,
Looks like you are on the way to a good combo.
Cam choice looks great to me especially for a big car, worst mistake would be to overcam it.
Long tube headers always win vs short tube headers or cast.
That said, those Cliffords are short tube so I'd guess them to be about even with Langdons. And the Langdons are iron which is a lot easier to live with and they wont rust out. I'd either go Langdons or long tube (about 36"-40" long).
BUT FIRST -
Seems to me something is wrong-
I wrote the DeuceCoupe Gonkulator to compute these (and other cars). I pulled out a file for a 59 Impala stock 235 powerglide, road test was 0-60mph 16.4sec (at sea level). Guessing in Wyoming at a mile high or so you'd see 0-60mph about 20sec in that stock 59. You can clock that pretty accurate with a stopwatch even if the speedo is accurate and stable. From 70mph up at altitude, I calculate that 59 Impala would take 14 seconds and about a quarter mile to reach 80mph, with an ultimate top speed of 88mph a couple miles later.
With dual carbs and a cam, your rig should already be better than this. Can you tell us details about the car itself, year/options/weight/trans/reargear/beltdrives/exhaust system/weight?
Which carbs are on there?
Theres several sizes of both Rochester B/BC/BV and Rochester MV carb. The little "economy option' Rochester BC 1-1/16" venturi is a real turd in my testing but the bigger Rochester BC/BV/B carbs are pretty strong, two of em should get that 230 moving pretty good.
I'd sort out what you have first, then add headers&duals next.
Post back your cars details and we'll figure it out!
