If youve done inlet manifold gasket. the rear bottom is a bugger to do up fully, and the gasket can shrink over the next few days / weeks depending on use, so go over them again in a week, and 2 weeks etc. as the fibre gasket shrinks before being settled, a bugger really you go out 2 weeks later and the bolts are loose. lol p.s. you probably should have done a few things while the manifold was off, hahahaa save you trouble later. ie everything under the manifold
jokes.