thats a silver top zetec (same as mine) goin by the inlet and the back mount im gonna say its out of a mk3 fiesta rs1800

see if it says HO on the back of the inlet

if its on standard internals 250 will be a good limit to leave it. have a look where the head meets the block to see if its got a decompression plate fitted it may have skimmed pistons of forged lol