i have a 1991 honda civic?

[Mallory R]

and when i bought it it was not running it needed a clutch so i put it in then when i starded it it would back fire alot fire balls would come out the intake manifold and gas was leaking from the headers so i decided to take the head off and cylinder 1 and 4 were real black 2 3 where good so do i need a new head or what should i do????

 

[? ? ?]

the reason for the back fireing was caused by the timing belt was =off or in need of a tune up