yaryekcim

i have a 1982 third gen z28. i had numerous probs and once sorting out one thing, something else props up.
its got a holley throttle body injection conversion on it. it was back firing thru the throttle body. later found it to be piston 5 rocker arms nuts had worked themselves loose so the arms werent attched!
fitted them back and ran again, but slight popping thru the exhausts. compression revealed low about 80-90psi on the right side. (5.0 302cu)
a friend suggested i had tightened the rocker arm nuts too tight (as i did them all but i didn't do it in the right order) so i readjustaed them to the book says, and now it won't fire at al, even though i have a spark and there is plenty of fuel. dad said the timing chain might of snapped, but i can turn the crank and see the valves move so it must be ok. i had a new one fitted two months ago.
any help please becasue its been sat there for 10 weeks now and really getting frustrated with it!
cheers from the UK!