72 Chevy k20 350 won't start

[72chevydump]

Hello all. I'm having some trouble with a dump truck I just bought. It had a cracked exhaust manifold when I bought it so I replaced them with a set of headers. Well in the process I dented the d/s valve cover. I removed the cover and used a block of wood and a hammer to straighten it all out. Looked pretty good so I reinstalled the cover. Started the truck and had a tap, tap, tap then shut off. Tried to start again and it would only run for 2 or 3 seconds then shut off. Did that a hand full of times then said screw it and pushed the truck outside. I figured from the rockers hittin the cover it wasnt letting the valves open all the way hense the stalling out right away. It sat for about 10-14 days until I got a new cover.

So today I pulled the old cover and replaced with a new used cover. New cover is straight and true. Put the new one on and tried to start it and it just cranks.

The old cover there were 2 light rub marks no deep gouges or anything just rubbed smooth a lil. I'm praying it isn't a bent valve.

Any and all info is greatly appreciated. Would like to get her going cause thy are calling for some snow.
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