Not rear sump is really weird.
You can tell 302 from 351 by looking at the water pump on the driver's side.
If it's right up on the head seam it's a 302.
If there's like 5/8-3/4" then it's a 351
But there were never EFI 351's in these trucks, so that's a tell right there
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.