1964 polara no power on slow speed accell?

[Heimedw]

I have a 64 polara 383. The car seem to have very little power from 1/4 to 3/4 throttle. When the secondary kick in it pulls just fine. Ok a little more info on the car. 383 stock to mild cam, 906 heads edelbrock duel plane dpn4 intake edelbrock 750 carb 1411. It did have 600 edelbrock was the same. I have check timing 12 dg, I have started to play with carb jetting. I went up in enrichment first no better and seem to be loading up. Going to go down next but not sure if it's going to help. Ow and the rear gear is 331 with 727. I keep hearing that a lot of people don't like the edelbrock cabs? Could the brand name of carb be the problem?

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[khryslerkid]

Did you check the timing advance when revving up?

 

[eric383]

Have you tried playing with the timing? More advance? If the dist. has a vac. advance canister make sure it holds vacuum. Here is an interesting article on tuning with a vacuum gauge. http://www.centuryperformance.com/f...ngine-Tuning-Using-a-Vacuum-Gauge?p=77#post77

 

[nm9stheham]

IMO.....An Edelbrock or Holley will not inherently have this issue. This sounds much more like a timing issue.

Start by looking at the whole ignition advance operation rather than the carb; if using vacuum advance, you might have the vacuum line in the wrong spot (have you checked the carb manual to see if your distributor's vacuum advance line is going to the ported vacuum port on the carb?), the vacuum advance pod may be stuck, the plate it moves in the distributor may be sticking. With only the primaries open, there should be a strong ported vacuum signal, giving you signficant vacuum advance.

This car is too early to have much in the way of vacuum advance porting controls, but trace the vacuum advance line from distributor to carb and see if it goes through any devices that may be blocking it.

What manifold vacuum level do you have in the engine when idling at around 800 rpm? It ought to be fairly high with a near stock cam. (This is manifiold vacumm under the carb, not the ported vacuum that goes to the distributor.)

Did you set initial timing per the manual (typically with the vacuum line blocked)? Stock timing may be a bit doggey....

And finally, check the valve timing to make sure that the timing chain is not a tooth off.

 

[Heimedw]

I have check the vacuum advance on the distributed but not the proper way with a gauge. This might get a smile or two but I took the cap off and pulled vacuum with my mouth and it did move free and held. I did set the carb up with a vacuum gauge and had 14 in at 800 rpm setting up low speed jets. The car has a hose from the right valve cover to carb(if it was a new car I would say it was a Pcv not sure if that is the proper term) anyway I took this as a emissions car so I put the vacuum on the ported vac port? If it's on the wrong one please let me know. It has a points delete module from pertronix. One question if I get a vacuum gauge that Will pull vacuum how much should it take to pull the advance to max? Ow and timing the car was at 13 from when I got the car. I dropped it to 10 and have it back up to 12 it seem to run the same at all three setting and yes it was with vac advance off with carb plugged.

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Also when I set up the carb I did it off the ported vac port was this the wrong port. I did try the gauge on the manifold port and the vacuum was low at idle 5 in?

 

[The Horvaths]

Manifold vacuum of 5" at idle seems to be very low. Even for a "big" cam. You might check for a leak.