Problems with OBS Tahoe

[damemorder]

Okay guys, I'm working on a '99 OBS Tahoe with a 5.7L. The intake manifold gaskets blew and put the coolant into the intake charge, but the owner kept driving it and got the engine very hot, She didn't think it was hot because the guage didn't say so... Anyway, I did a pressure test on the coolant system and for compression, replaced the gaskets and adjusted the rockers. When I started it back up I got a lot of rocker noise. I pulled the valve covers again and started to adjust them while running, But I noticed what seems to be a big problem, There's no oil coming from the pushrods, at all. I put a mechanical guage on it and I get 43psi. I'm not sure if the lifters have pumped up yet, But shouldn't I get oil at the pushrods anytime she's running?

I'm beginning to think maybe some oil got burnt up in one of the passages and is blocking flow, What's the chances of that? If that is what happened is there any way to fix it other than a full rebuild?

My neighbor is an older mechanic, He said to just let it idle and they'll pump up quck enough, But they haven't. In total since I pulled it apart it has idled for about 45min, But they're just not pumping up.

Can I get some guidance and a little advice?