Similar issue to B2G707 engine rattle

[Litchkar]

71 Challenger with a 1969 340 and a 727 trans.
When I start it it rattles and shakes when cold below 1,500 rpm.
Pulled each spark plug wire, but can’t pinpoint which cylinder.
Approx 3,500 since it was rebuilt, aluminum heads, adjustable rockers, cast iron exhaust manifolds.
No exhaust leaks, compression ranges from a low of 185 to a high of 200 psi.
Checked all cylinders with a thermal thermometer and all seem to be hot.
Once warm the noise is very slight at idle almost a ticking sound.
60 psi oil pressure cold, when I pull the valve covers plenty of oil up top.
Only thing that seams off are spark plugs are reddish brown.
Adjusted the lash, timing and fuel mixture, but made no difference.
Once warm, runs good and idles smooth.
Is it in the bottom end?

 

[Adam]

Adjustable rockers will make some noise. My first guess was bent pushrod, but you probably would have noticed when you adjusted the lash.

I think if there was trouble in the bottom end it would not go away when warm. Perhaps your carb is dumping gas, as it warms up the gas will atomize better.. do you have a different carb to try?

 

[Chryco Psycho]

vacuum leak ? maybe into the brake booster ?
Noise could be just exhaust leak

 

[AUSTA]

Yes vacuum or what pistons did you use could be piston rattle when cold
The problem may be several minor rather than the same problem.
How much choke does it have when cold
The air bleed may be slightly out when cold

 

[Litchkar]

Carb is a three month old EVS-2 650 cfm. Almost no choke set in it. Boooster is new.
I adjusted about 15 more degrees into the timing and it almost is gone. When I drove it it felt good, but now I have clicking sound thru radio when engine is on. Awaiting my new plugs Champ RC12YC to arrive, old ones look like crap.
Distributer is also new. Thinking it is in electrical system. No exhaust leaks.