replacement intake studs

Silver seal has them.

http://www.silver-seal.com/product/6403/Manifold-Stud-For-225-Slant-6-Dodge---516-18-24-x-188.html

Anybody know where to get the 5/16 bolts that hold the manifolds together bythe carb?

They are almost 3-1/2" long and have about 1-3/4 inches of thread. Standard bolt that size does not have enough thread and fullyl threaded that I found was only grade 2. Originals were grade 5, but would prefer to go to gr 8.