I just put a new a new exhaust system on my 70 Mach 351w, since all the exhaust partswere getting replaced I had my exhaust manifolds sandblasted and I painted them with Hi Temp manilfold paint. I also replaced my valve cover gaskets and oil pan gaskets at the same time. When I fired it up for the first time I immediatly noticed that I must have reversed a couple of spark plug wires by the roughness of the motor. I immediatly shut it off, corrected the problem and restarted the motor. I now have a terrible loud metaltick, appears to be coming from thepassenger side, the car has been sitting for awhile but is started occasionallyand always runs smooth as a top.I have retightened the exhaust manifolds. The tick is loud and speeds up with the RPM's This is the original motor, low miles never rebuilt. What the heck could have happened it wasnt doing this before I replaced the exhaust and gaskets, do you thinkI have a collapsedlifter or a bent push rod? The engine fires right up and runs smooth , except for the loud tick. Any advice would be greatly appreciated.

Thank You

 

Ticking can be an exhaust noise (among a lot of other more serious possibilities). Is it possible one of the exhaust manifolds is warped?

 

While it is possible that the engine may have become damaged, I would be more prone to think that you have an exhaust leak at one of the manifold/head juncture points....

Leaks here can sound like a tick or even a little like a knock.

Sometimes manifolds can contort themselves after removal from a head. This contortion can cause a manifold to leak even when assembled properly. If this is your problem, I don't know if there is a solution other than replacement. It seems as if a machine shop could true the manifold up, but I have never heard of this being done.

Check carefully around the manifolds, top and bottom. Sometimes these leaks are hard to spot.

 

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make sure the spark plugs are tight I had a tic from one that was hard to reach and it made a ticing sound . which went away when I found it.

 

Its a Collapsed lifter in # 2 cylinder, I was going to change out the intake manifold and carbanyway, strange how these things coincidently happen.

Thanks for the responses!