I'm taking it the engine is in the chassis. Best way Ive found to do it is slide the head in from the right side. You have to do it with the head nearly touching the down tube that is directly infront of the engine. It'll take some finagling. Once you have the head in the frame and all you have to do is move it backward and set it on the cylinder, put the 2 front bolts in. You'll have to tilt and turn the head to get enough room so the top of the bolts don't hit the frame. You should be able to tilt the head forward, against the town tube, and slid the bolts in from infront of the cross tube the steering stem mounts to. Once you get the front bolts in all you have to do is hold them up and set the head on the cylinder. The rear 2 bolts usually go in without issue. If the bolt heads hit the motor mounts on the frame, gently lift and "jiggle" the head some to get the bolts to drop in. You wont be able to move it much because of the front bolts being in and the locator pins in between the head and cylinder, but there is usually just enough. Try appling hard pressure to the bolt heads 1st and they may drop in. The 2 long bolts go on the left and shorts on the right, if i'm not mistaken. When you look at the head 2 of the bolt holes will be higher than the other. Obviously the higher bolt holes are for the longer bolts. If you want easier pull the bottom end out and install the head on the bench and then reinstall the whole engine.