mk1 caddy 1.8 head on 2L bottom end need help

so i have got mk1 caddy 1.8 head that come off my old ex engine it now on my 2l ady bottom end
my problem is the engine will only rev up to 4000 or 5000 i have bin playing with the timing but not had much lucky
did know if it was down to the  distributor out of my old ex engine did know if it had a enough advanced or do i need a different  distributor 

so what distributor has it got in it?