you could try running some seafoam and running it a couple hundred miles and do another oil change. there is/was alot of crap in it and it could be blocking passageways to feed the lifters

After Re-installing the intake manifold the truck will not run while the mass air flow sensor is connected , it starts then stalls and dies . My first thought was to check for a vacuum leak somewhere around the tubes and seals . A vacuum leak was found at the map sensor grommet ,and the engine side of the brake booster vacuum hose . The grommet required was not carried by any local parts dealer nor did a local gm dealer have one in stock. , after five or six days i have my part via mail order. I replaced the rubber grommet and booster hose yet the engine still only runs with the maf disconnected , what else could cause this ? I also noticed that if i cover the pcv tube that connects to the air intake hose it creates a vacuum on my finger causing the engine tick to go down about ninety fiver percent .

still sounds like a leak somewhere

Just so people don't get the wrong idea this is still broken . I could win an Olympic medal for all the running around and lifting I have done to it so far. Here is a list of what I have done in my off days .

Lower and upper intake (pulled twice )
Lifters removed (pulled ,inspected, disassembled ,cleaned ,and re-assembled )
Push rods (pulled,inspected ,cleaned ,inspected again , 3 were replaced .
Rocker arm studs (replaced all 12)
Rocker arms (inspected , cleaned , and re-torqued ).
Exhaust manifold right side (inspected for cracks ,and replaced gaskets).
Exhaust manifold right side (untouched).
Doughnut gasket passenger side (replaced)
Oil (flushed with seafoam ,atf4, and replaced with 10w40 reduced the tick).
Tune up (replaced oil,plugs,wires,air/oil filter ,and added b12 chemtool to fuel.
Egr valve (cleaned with qtip and b12 chemtool )
Map sensor (replaced)
pcv valve (replaced)
Mass air flow sensor (cleaned )

The engine was run without the valve covers and no lifter tick was found.
The assumption is the engine was ticking from multiple sources .
After the intake was pulled and the lifters cleaned the tick reduced lightly .
When I added 10w40 oil in place of 5w30 the tick reduced yet further .
After all of this i have only managed to reduce the tick forty to sixty percent.

Anyone got any idea'* ?

likely have some residual crap in the oil passage ways i would leave the proper weight oil in it but run somemore seafoam and run it for a few hundred miles and change the oil again. may have to run it a while to clear with a oil with good cleaning package

The engine spec says 5w30 or 10w40 , the oil added was the largest weight oil still within spec. I plan to seafoam it again in the morning .
The truck has not been driven that much since i acquired it , letting it tick for a few hundred more miles may just fix it .

mine ticked, there was sludge in everything, probably a inch thick in the lifter valley. i just cleaned everything the best i could, pulled the rocker covers cleaned all that, ran some seafoam for a hundred miles then changed the oil to normal 5w-30 valvoline. it got better the more i drove it. now if it ticks at all its just for a minute or two while warming up