To answer your question about Langdon's Holly/Weber 5200 carb/adaptor/linkage....I have one on my stock 235 and it eliminated all the typical problems you encounter with a Rochester.
My truck is driven daily, the engine has good compression, was starting and running fine but was leak-prone and throttle shaft was sloppy. Typical idle problems and driveability wasn't up to par. The Holly/Weber, out of the box, eliminated all my carb problems, improved my mileage, and makes it a pleasure to drive.
Once you've followed the guys suggestions and have a sound engine with good compression, IMHO you would find the Holly/Weber a vast improvement over the Rochester. Hope this helps.
