340 exhaust manifolds???

You don't need a kit. With one exception, everything needed can be purchased at an industrial/farm or other good hardware store. The one exception are the heavy Bellville type washers. These go on the 4 studs and are the best type of washer for the purpose.

You will see some of the mail order places hawking long nuts. I haven't used them,or really figured out why the were needed. Some one with more knowledge about originals and restoration should be able to chime in on what those were for.

If there are any issues they will be that the mating surfaces are not perfectly flat, heat valve stuck (if its still there), cracked or broken castings. The gasket to the headpipe is a bit of an oddball with about 2 5/16" ID. Accurate Exhaust has them in stock. Buy a few extras. If the mating surfaces to the heads are good, or gan be trued by hand lapping, no gasket is used. OEM used metal heat shield/gasket on the driver side to help protect the spark plug wires.