My '77 Ford F-250 3/4ton pickup with a 460 engine is supposed to redline at 
4000 RPM's, I've only had it up to 3800 (that seemed to be all the faster it 
would go and it was screaming at 108mph) so I would say that your 351m 
engine's "redline" is somewhere beyond that since you have fewer cubes and a 
shorter stroke.
My best suggestion is to call the local Ford dealer and ask for the shop 
foreman and ask him/her, if he/she doesn't know call a machine shop and ask 
them they might know.
As someone else said on this BBS "when" your engine flies apart depends on 
it's condition (how old it is and how many miles it has on it) an older 
"loose" engine is more likely to have it's rod bolts fly apart at high RPM's 
that a newer engine would.
I hope this has been helpfull.
--- QuickBBS 2.81 GoldBase
---------------