Motor Stands What's Wrong

[specks70]

Ok, Have been reading a few posts and looking at pictures on this forum also; and have yet to figure this one out.
My motor stands will only fit in the back holes of my frame. And the 350 motor I'm installing has high valve covers plus an electronic distributor.
My 70 was originally a 6 cylinder and the stands I took from a donor truck that had a 283 motor but was also a 6 cylinder originally. I removed those roughly a year ago and cannot remember where they were located on that truck.
I understand I can use the back holes however I would like to use the front ones for room.
Could someone please explain why my stands will not fit in the front frame holes as shown by other posts on the forum