I would like to refer you to this page: 386DX40 build
at least two members here(myself included) have built a 386-40 system and the 2nd picture shows EXACTLY how math co-processors fit into the socket. take care inserting the co-pro into the socket. If nothing else, insert it and take a picture and show us, BEFORE powering up and most everyone should be able to say if it is correct.
Once you get it all setup. you MUST benchmark it!!!! We tend to use 2 benchmarks:
First, thanks to all people
I bought on ebay 32mb ram in 30pin SIMM, a ET4000AX 1mb ISA, and a ISA SCSI card + 8GB HDD
When RAM, scsi, and video arrive, i will take pictures of mobo + FPU and do all benchmarks
For sure in less than a week, all the components arrive, and I can assemble the 386 😁
THANKS!!!