I have put a complete 46 on an 87 S-10 frame. Thanks to E-Z Swap it was a easy build.
E-Z Swap I am thoroughly impressed with the kit. I am sure you can get just the part of the kit to mount the radiator support to the frame. It is engineered to do just what you need. The front fenders mount to the front of the cab and to the radiator support and no where else.
Pic of radiator support kit If you have questions contact me.
Frank Cox
Cox Custom Cars & Restorations