what kind of performance can i expect from a basic rebuild on my 84 351H.O. rings bearings seals etc.

 

All depends on what parts you use....if you rebuilt the bottom end to factory specs or similar...it'll handle a lot of extra power...but how much power you get depends on what kinds of top engine parts you use. A 351 can run anywhere from 0 hp when dead (haha) to 450++ naturally aspirated.

 

What do you mean by performance? If you change your bearings seals etc. and take it back to stock, then you could expect a stock performing engine. Unlike 302HO, 351w HO means little to nothing, other than a 4bbl intake and carb, there are minor differences in the cams but still nothing to take note of. Just a thought