1973 340, want more power.

Can you post a link to a good converter to match up to the 3.91 gears?

This is who I went with: Performance Torque Converters - Specializing in Race Converters & Transmissions Design & Manufacturing

But you can talk to Lenny at ultimate. Or Pro torque. Or anyone who makes custom converters. I suggest filling out their spec sheet IN FULL. And they will get back to you with a price and timeframe. Then the converter will be built to your EXACT specs. My custom converter from PTC was LESS than an off the shelf B&M unit. Built to my exact car. Billet front. 9.5 inch. 3000 stall. Good for the street. It was very easy to work with them.