Custom parts

Where is a good place to get a custom shaft made with splines the shaft will be used for an input shaft into a transfer case for a pulling truck

http://www.tcsproducts.com/products/product/tf727-max-lug-pump-gear-set/
They might be able to help,worth a phone call.

Try Liberty Gears, They made a input shaft out of M300 material for me.

G-Force Transmissions

Mark Williams, Moser, Cass at Dr. Diff and others that sell trans and differential parts
Maybe get on one of the tractor and truck pulling web sites to see if any one of those type firms advertises on their or if any of the members know of a company that will help you

Ok thanks everyone