It would probably be cheaper to buy a late model shortblock. Otherwise, you can get a hydraulic roller conversion kit from crane or comp cams. If you do that, you are stuck running their special, and expensive, small base circle retro-fit roller cams. I had the comp cams set up about 10 years ago when it first came out. It was over a grand back then for cam,springs,conversion kit,roller lifters,pushrods....lots o dough!
what year is the block he has. i used a motor out of my old 90 truck and used that for my baseline. the block was already roller ready with the drilled and tapped holes in the lifter valley. all i needed was a roller cam, lifters,pushrods and the spider bars from the junkyard or jegs and it would be a roller cammed engine. if the block has 2 holes in the lifter valley floor that are threaded already then that block is roller ready and he won't need a small base circle cam. this is the way i understand it. otherwise everything else just bolts on just fine.
Its the ability to drive your hydrolic roller motor and not have to adjust the valvetrain all the time. I know so many people who have well over 100,000 on their 5.0's with stock rockers, lifters, and they have never had the valve lash set besides factory.
A roller motor is a much better setup for longer life and less maintenance.
odds are it isnt a roller... I think the only roller 351 was in the lightning back then..
just go with a hyd. flat tappet cam... a whole lot cheaper and easier.. and there are a ton of choices for a cam..
I'm pretty sure they didn't have a lightning back then. Not till the early 90's...I think. But you're right about it probably not being a roller. The trucks didn't get the fancy injection until 87 or 88 I think.