I did pressure test and have no pressure in 1 - 4 and 150 in 5.
I could try and blame the tensioner, that has a bent arm (the one that locates against the block) so that is not necessarily spinning quite true, also that was not tightened fully when I did one of my timing tweaks - and problem occurred directly after that. However, my pulley marks and cam and crank all lined up before and after that. It is not as though I skipped a few teeth.
I like your comment about the loose looking belt. But, it is hard to get on as the tensioner force does go against you. It is not loose in the sense of doing the job intended for it. The pulley cogs are same as old camshaft pulley cogs and checked them for size. But I agree that the belt looks floppy. Maybe it is the camera tricking or that the belt is a little bent in places around it due to me prying it with my fingers ...?
I am ruled out that I did 180 degree mix up on timing or occurring afterward. Once the cams are set in the cover it is impossible to reverse pulleys or crank due to valve interference. You loosen belt and try and turn pulleys or crank and they interfere after about 30 degrees each way. I can't flip 180 and I know that all the marks were checked and lined up from my install. I spent time looking at photos of the crank align for example. I have used lock pin in the block and that also fixes the location of the crank mark. Same care was given to the cam slots.
I am process of removing cover and head and look at the valves. But, this anaerobic sealant is like gorilla glue so prying the cover is taking time.