[Tim Brewer]

Don't remove the manifold. And I wouldn't recomend adjusting the rockers while the engine is running. You didn't say wether you have hyd. or solid lifters, each have a slightly different way of adjusting them. Each have to be adjusted with the piston at tdc and the valve closed. If you have a Ford manual, it will tell you a sequence for adjustment for doing 3 or 4 cylinders at a time by turning the engine over a little at a time. With the valve closed, then and only then you can tell by hand if you have any loose rockers. Solid lifters you have to use a feeler gauge, and hyd. lifters you tighten untill contact and then give them another 3/4 turn.
Hope this helps...
Tim