New cam wont idle under 1050 rpm ?

I just swaped out the cam in my 408 LA stroker and i cant get it to idle down.The new cam is an Iskenderian solid flat tappit with 300/300 advertised and 254/254 @ 50 duration.It is a 108 lobe seperation ,that i installed straight up.I have no complaints about how it runs (the throttle response is snappy),just thought it should idle a bit lower.If i idle it down to 900-1000 rpm it starts thumping real hard and then tries to die .Old cam was a 112 lobe sep and would idle at 900 real easily .Is this normal witha cam of 108 lobe sep ? I also ported the W2 heads and had them rebuilt ,but wouldnt think that would affect idle .I have no vacume leaks ,but its only pulling about 7 inches of vacume .I knew that a lower lobe sep # would hender idling manners ,but didnt think it would be so drastic .Its a race only bracket car ,so i dont care what it idles at ,just want to make sure its normal .Here is a vid of it ,and sorry for the bad audio .My camera and my Dodge dont like each other ...

http://youtu.be/30XmDAKQn-8

Did you open up the mixture screws at all

you may have to run more initial timing,recurve dist.may also have to change power valve in the carb.if it has a stock 6.5 its probably opening some and making it to rich.

As said you might need more initial timing.

PV has no effect at idle,unless it is blown.

Race car / bracket car so whats the problem. My motor rarely idles under 1250 and when I set the tranz brake I run it up to 2000.

Didnt say it was a problem ,im just asking if its normal with a cam like this is all.I didnt touch the mixture screws at first and it wouldnt idle like it did with the other cam .I then marked their posistion and tried to open them up reading the vacume gauge and it made it worse ,so i put them back.I had them tuned perfectly with the other cam.Oh yeah ,it needed more intial timing ,and i gave it to it.Just a hair more and it tires to kick back when its warmed up...

Is your timing locked out or are you using advance...
if you have advance you nee to curve it... carb work
is a balancing act... you need to get the mixture screws
right with the amount of throttle opening... since you
have it running turn down the throttle opening so its
still running then reset the mixture screws... then
do it all over again till you get the idle to where
it idles good and accelerate strong..... but timing
is first
EDIT
The cam I have in my 416 is bigger and it'll idle
at about 850-900

Thank you MR PBody .I will give it try ...