Okay heres the set up. I bought a mustang with a cracked block. I wanted a project car. Well i am putting an explorer engine in it. I already have all the parts for it. When i bought the used engine it had 65,000 miles and i could turn it by hand. I bought a Trick flow stage 1 cam, i took the valve covers off along with the manifold, pushrods, rockers and rollers, and everythig needed to gain access to the cam. Pulled it out and slid the new one in. I have yet to reinstall the rest of the valvetrain because now if i try to turn the engine via the crank it only goes about 1/4 of the way both clockwise and counter. What could this be? The heads are still on the motor incase you need that info