Posted By: 74RR
Sluggish 440 w/509 MP cam. - 09/21/09 08:45 PM
I've got a 440 with a 509 cam = low vaccuum. Right now I have a Holly 750 w/vaccuum secondaries.
If I changed to a double pumper would give me better throttle response?
Posted By: DaytonaTurbo
Re: Sluggish 440 w/509 MP cam. - 09/21/09 08:58 PM
During normal driving a vacuum holley should be no better for throttle response than a dp holley. I would be more concerned about your power valve opening during normal driving if your vacuum is that low.
If your throttle response is sluggish when you nail the throttle, then tuning is your problem. I would suggest investing in a tuning kit with jets, pump cams/shooters and secondary springs and making sure your power valves are suited for your application.
Posted By: dulcich
Re: Sluggish 440 w/509 MP cam. - 09/21/09 09:15 PM
Generally, yes it will be much more responsive with a DP. You want to run some converter with that cam too, and headers and gear.
-dulcich
Posted By: 74RR
Re: Sluggish 440 w/509 MP cam. - 09/21/09 09:16 PM
Ok,thanks for the reply. If I stand on it from a dead stop I can't even catch rubber.
Posted By: Dodgem
Re: Sluggish 440 w/509 MP cam. - 09/21/09 09:22 PM
Make sure it has no vacuum advance hooked up and has mechanical total 38 and all in by 2000. (or less RPMs) carb is not the problem.
Posted By: Baxter61
Re: Sluggish 440 w/509 MP cam. - 09/21/09 09:23 PM
put some timing in it, make sure your getting a solid squirt of fuel when the throttle is cracked, and check for vacuum leaks.
Posted By: CH3NO2
Re: Sluggish 440 w/509 MP cam. - 09/21/09 09:26 PM
what's the real compression on that 440?
Posted By: Dougsmopars
Re: Sluggish 440 w/509 MP cam. - 09/22/09 01:24 AM
I had a stock HP 440 1969 motor. Car had MP electronic dist and a factory six pac. Car run super with stock cam. Installed a 509 and car turned into a dog. Was a 4 speed and yes it would roast the tires but a lot less power then stock cam. We tried a lot of things including timing. Shop that installed the cam did it the old fashion way dot to dot but 4 degree advanced. I sold the car because it pissed me off. I've come to the conclusion that those 509 cams really need to be degreed in not just dot to dot.
Posted By: Mr.Yuck
Re: Sluggish 440 w/509 MP cam. - 09/22/09 11:43 AM
2 of my favorite topics, 750DP's and 509 cams. You should have enough gear and conert for the 509, now how about compression? If you don't have 10:1 it's not going to work well. The vacuum carb is terrible for a low compression 509 cammed car. (been there and it ran like poo poo) A DP will help but you're going to have to tune it. A 750 DP is way beeter IMO than the vacuum modle. What else is done to the motor? headers? intake?
FWIW my old 440 w/ 509 liked 38* total at 2400 no vac advance and you won't really feel it pull until 3k then watch out.
Posted By: Rapid340
Re: Sluggish 440 w/509 MP cam. - 09/22/09 12:04 PM
I would consider two things (in this order).
1) check/recurve distributor for about 18-20 degrees initial timing, 38 total.
2) if still unhappy, advance the cam to 102-103.
Posted By: gch
Re: Sluggish 440 w/509 MP cam. - 09/22/09 12:16 PM
I disagree on the throttle response with the vacuum secondary.
Take a big cam with poor low speed response and slam it with a double shot of gas.BOG.
I think the vacuum secondary would offer better response down low.He may need a different spring in the secondary to fine tune it.
Advancing the cam a few degrees and running 15-18 initial timing should make a huge difference.
Posted By: joedust451
Re: Sluggish 440 w/509 MP cam. - 09/22/09 03:32 PM
I've run a few .509s, i wanted the sound of that cam, but the 1st. thing i did was raise the compression with some decent FTs, either KB237s or TRW 2255s, my 1 dart i installed a TM7 & 850dp., had 3.91s, Cheapie 4500 stall, MP dizzy, MSD box, drop the cam dot to dot on all of them, had the int. timing around 16-17*, total was 38* & light springs, they all ran great, always had to run MTs, street tires never had a chance. Those cams do like compression/timing & stall.
Posted By: moper
Re: Sluggish 440 w/509 MP cam. - 09/22/09 03:51 PM
This is normal for a 440 with too low a static ratio for the cam, and a cam that is very poorly made. What are the cylinder pressure readings? Blaming the carb is a hip-shot answer. Carb has nothing to do with it at this point, and vacuum carbs work off engine demand. If the enigne is wheezing, it wont work and tossing more fuel via accelerator pump at it wont help in the least.
Sorry, I edited it.. I missed a "4" in 440...lol
Posted By: TonyS451
Re: Sluggish 440 w/509 MP cam. - 09/22/09 09:27 PM
I too have witnessed first hand how poorly a 509 cam will work without the right mix of parts. Your gear is fine, but that cam likes every bit of a 3800 stall (and then some). It will also wake up with 20+ degrees of initial and 36-38 total timing. The vacumm secondary carb will work, but the dp will be snappier when in proper tune. That cam can make some good power when all your ducks are in a row.