'85, 190 E

I HAVE 1985, 190-E, TIMMING CHAIN BROKE AT LOW SPEED
(2-5 MPH) . SHOULD I REPLACE WITH THE USED ENGINE WITH APPROX. 68000 MIS ON IT OR SHOULD I REBUILT THE HEAD.
IF I REBUILD THE HEAD, HOW LONG DO U THINK THE BOTTOM WILL HOLD UP. AND I THINK THE CHEAPEST WAY TO DO IS REBUILT THE HEAD?? AM I CORRECT.
THANKS GUYS AND GOD BLESS
6KILLER