We need details.....Lots of them please.

What cam do you have now?

 

Intake Duration at 050 inch Lift: 227
Exhaust Duration at 050 inch Lift: 235
Duration at 050 inch Lift: 227 int./235 exh.
Advertised Intake Duration: 281
Advertised Exhaust Duration: 289
Advertised Duration: 281 int./289 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.554 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.562 in.
Valve Lift with Factory Rocker Arm Ratio: 0.554 int./0.562 exh.
Lobe Separation (degrees): 109

Cam is installed straight up

What other details would you like to know?

 

In a 400ci with some CR I'm not surprised you not getting what you want.
Turn down the idle, fatten the idle circuits, and take out some timing will get you closer to the sound you want.

 

Its a built up 400 9.5:1 CR weiand dual plane intake, headers, 750 carb, full roller rockers, ported iron heads. It had the idle quality i loved but then it disappeared. Is this normal with engine break ins. Is it something i should be worried about or should i just leave it?

 

It's normal to have a change in pitch as the ring seal and the cam wear patterns emerge but this seems a bit dramatic. Perhaps not.

I'd check the lash and other basic engine stuff like, timing, AFR, leaks and such and if you like it, keep it.

 

Yes i thought it seemed to be a dramitic change aswell. I was driving home one day amd noticed the change while driving. The A/F seems to be correct looking at the plugs and im still messing around with timing trying to get the most timing without detination. I will have to pull the valve covers off and check to see if things loosen up some and causing excessive lash. Thanks

 

I assume this is a flat tappet cam and I assume the lobes are wearing down... the spec.s look like a short lifespan 'extreme' cam... as I recall, Ford 400's have oiling problems that need to be addressed when going hyper... or you may have bent some valves from overrevving...

A compression test can reveal bent valves... or incorrect valve lash...

Back in the '60's, my friend's Road Runner bent a valve when the cam sprocket bolt came loose... we listened to the exhaust pipes... one side sounded rough, other side sounded smooth, so we pulled the head on the rough side... no problem... turns out it was supposed to sound rough... bent valve was on the smooth side...
.

 

I assume this is a flat tappet cam and I assume the lobes are wearing down... as I recall, Ford 400's have oiling problems that need to be addressed when going hyper... or you may have bent some valves from overrevving... ...

More or less an X2 here. If the character of the idle changed suddenly I be suspect of the lobes and lifters going away.

Bogie

 

maybe recheck your timing to see if one of the weights is stuck and did not return all the way advancing your timing a little at idle, just a thought