I have a '75 Low compression 440 w/ this cam Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,200-5,200
Intake Duration at 050 inch Lift: 218
Exhaust Duration at 050 inch Lift: 218
Duration at 050 inch Lift: 218 int./218 exh.
Advertised Intake Duration: 268
Advertised Exhaust Duration: 268
Advertised Duration: 268 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.454 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.454 in.
Valve Lift with Factory Rocker Arm Ratio: 0.454 int./0.454 exh. lift
Lobe Separation (degrees): 110

It runs great except for idling in gear....I can't get an idle set that's acceptable. I.E. the RPM drop is too large when put in gear. I've tried several carbs over the years and they all have this basic issue....Currently it has a Carter comp series 750.... What can I try to get this cars idle quality better? Thanks

What's your initial spark advance? The more, the merrier, if your distributor has a curve that will tolerate that much once you're on the road. That usually means a custom curved distributor.

My old Dart's 440 was also low-compression, and I was running a MP 284/484 beast, with a TIGHT 11" converter. Yeah, not a great combo. Idle vacuum in gear was about 8", in neutral was about 11". Unfortunately, I was a po' collige kid and couldn't ever afford to get my distributor curved - and didn't know how to do it myself. So, 12* was about all I could manage and still drive the car at highway speeds. If I could have gotten 18* it would have been a lot happier.

Clair

try alot more initial timing (no idea where yours it at).. mabey 15+deg.
also try to fatten up the idle mixtures to the highest vacuum reading.

Yea it has a sick amount of initial advance....I'm thinking about changing the cam...to something smaller but the cheap summit cams didn't appear to be much smaller....It has the classic problem of the idle speed is so high (in neutral it has to be this high so as to not stall in gear)that the idle mixture screws dont seem to do much....( in gear the idle quality is so horrible that the engine barely stays running)

Put the stock cam in there. The 440 HP cam sounds like the cam you need. Low compression makes the idle worse, so that's not helping your cause, either.
-dulcich

you can tune that out. try to fatten up the idle mixture.
what kinda vacuum at idle and in drive?

I've tried restricting the idle air bleeds with no success, the vacuum #'s are like 12" in gear and 18 out of....If I can get a cheap small cam/lifters I'd switch in a minute....Anyone wanna trade? Factory HP for a Comp 268? I have the matching lifters in order.....

I had a comp 268h in my college car 1968 gts 383. it was great with a 4 speed and a 780 holley. but it was a real dud with a 750 carter and a 727. It is not really that big of a cam in my opinion I think with a tuneable carb it would of been okay. The carter just didn't have the pump it needed. If i pulled out on the choke it was much better out of the hole but then thats not really a cure for a bad carb.
Have you tried a Holley double pumper style with four corner idle I have found that they work much better than the afb style on modified motors

No I've never tried anything but Edlebrock's/Carters and a Thermoquad on this motor. I have no doubt a new $5/400 carb might fix it, as I have a Speed Demon 850 on a similar 451 I own and was able to tune it. But I just want this car to run nice so I can sell it. BTW it's a 64 Polara vert so it just needs a nice cruiser motor. I just need to find a deal on a stock type cam....

If you got a carb that runs good on another engine why not try swapping it to see if you can localize the problem to the Ede carb.

Rick, if the vacuum goes from 18 to 12, that does not sound like the cam. What kind of rpm drop do you get going from neutral to in-gear? I did not understand your comment about the initial timing. One thing to look for with your timing: be sure that the mechanical advance is not partially coming-in when idling in neutral. If you have some mechanical advance in when in neutral, you will lose some or all of it when you put it in gear, causing a large difference in neutral to in-gear idle quality. I have not run that cam but have run others that, on paper, are larger than that one and had more than 12" vacuum in gear.

torque converter

What is your idle speed? You should have no trouble getting a cam with 218°@.050 to idle with 7:1 compression. What distributor/advance curve?

with tom, needs a verter,try a stock high stall for it

Torque converter is wayyyy to tight. You will be surprised how different it will run with the correct converter.

your problem is not the type of carb!! its how its tuned. makes shure you are useing ported vacume. pull the idel screws out and blow compressed air thruogh there. put them back in all the way and then back them out to 2 1/4 turns. after that turn them in until the idle drops 100 rpms. then back up 1/2 turn on each side. if timing is correct and his is done. it will run great.

note a engine with 18 inches ideling is not overcamed. also a hp 440 cam is gust as big as that cam.

I know how to set the idle mixture thanks Nick....I'm more prone to go with the too tight torque converter theory, as the symptoms really agree. The tranny is a stock BB push button with an unknown converter. The cars slams into gear and jumps from the higher unloaded idle RPM and then barely lopes along in gear. I'll get some actual numbers on idle speeds and vacuum later today. I agree this cam doesn't seem this big and should be able to work....But I haven't to make it so in 10 years of messin with this. Yes this car has ran this way for a long time.

the convoter is very tight but a 440 with 18 inches @ idel should do fine. just try blowing out the air bleeds for the idel circut and you may see a good improvement. also set the carb on the rich side and that will help alot. just dont wast you money on things unless you have tried doning all of the tuning steps first. it may help to call the edelbrock tech line. tell them you have a 1406 carb (just like the carter) and they will help you with your suggestons. good luck.