Ticking noise with new engine

I just put a new crate engine in my 86' GT. It's a 306 w/ flat top pistons and large valve reliefs (plenty of room), ported GT heads with larger valves and an e303 cam with stock rocker arms.

The first time I started it up I heard ticking coming from the passenger side valve train. The ticking gets more frequent when you give it gas. I'm thinking bent pushrod, or worse bad lifter. So I got p.o.ed and took off the valve cover, checked over the pushrods (which looked fine) and retorqued the rockers (which were also fine) and started it again (w/o the valve cover) and no ticking noise. Okay so I put the valve cover back on and started it. Guess what ... it's ticking again.

So I'm thinking because there was no ticking with the valve cover off maybe the lift from the e303 cam high enough that the rockers are hitting the valve cover. Any thing else I may be missing?

Should I immediately purchase a bigger set of valve covers or can I drive it like this?

ls1beater4eva said:

well i doubt that it is rockers hitting the valve covers seeing how you stated that they were stock, i would check and maker sure that you dont have a dead lifter or a tiny exhaust leak on that side b.c that is what it sounds like to me. i have a had i little exhaust leak and sounded like that befor so just double check your header gaskets and collectors

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But wouldn't either of those still cause the ticking noise when the car was running with the valve cover off?

I went ahead and purchased some taller valve covers this afternoon. If that doesn't fix it I guess I'll pull the intake and replace the lifters and pushrods.