Need help - replacement axle bolts

Anyone know of a good source for replacement bolts for my 56 chevy rear axle? The bolts are splined, pressed into the housing and bolt down the third member. They look like a wheel stud but are smaller dia. (3/8"). I've been to my local auto parts stores, axle shops, ARP website, etc. and am striking out.

 

Scroll about half way down the page of this link until you see 3/8 housing studs. These should be what you need. Mittle Bros. is the name of the company.

http://www.mittlerbros.com/rearend_parts_acc.htm

 

Thanks for the link! I'm ordering a set today.