351 windsor blowing oil from breather and valve cover
 

hello fellows,
i bought this truck it was leaking from the valve covers and the oil pan we put new valve covers on and redone the oil pan gasket then i proceeded to blow oil from the dipstick and the valve covers i put the old valve covers on im leaking oil straight onto the headers now its only when i get on the gas real hard seems to be building way too much compression i do have a breather on it but still getting alot of compression
any ideas would be helpful

Do a compression check, it's possible it has bad rings or a hole in a piston.