Quote:

---

Quote:

---

What cam is in the thing? That will be the biggest factor in idle quality.

Also, how is the timing? Initial and total.

Could be mechanical interference somewhere. Disconnect the throttle cable and see if it resets.

---

The cam is a solid flat tappet .540 [Email]242deg@.050[/Email] installed at 104deg

Would love to hear the engine actually idle with it. I tried to set the timing as best I could but with the rpms so fast I can't really read it. Any suggestions?

I will disconnect the cable tomorrow and see if that helps.

---

I had a similar issue with my car. I ended up having to set initial timing at 18 Deg. w/ 35* total. All in by 2500 RPM and get a carb setup with 4 corner idling. I also started out with a 850 carb with only primary idle mixture screws and a dist with factory advance curve. I believe the carb was my biggest cause of the idle problems. The carb is probably not setup for that large of a camshaft. The idle vacuum is low and provides a weak signal to the idle circuit. With only front mixture adjustment and not being able to change out the air bleeds it will be almost impossible to dial it in. I would start by taking the carb off and baselining the throttle plates. There is a good video in tech section on www.4secondsflat.com. When I looked earlier the website was down. Also, look down in the carb with engine at idle and make sure the boosters aren't dripping fuel. Good luck!

EDIT: I just noticed you have proform main body. You may end up needing a rear metering plate with mixture scews and adjusting air bleeds for your combo.

Quote:

---

On the damper...Use some paint or fingernail polish on the timing mark....Lots easier to see!!

---

Quote:

---

Quote:

---

Quote:

---

Quote:

---

Quote:

---

Should be able to idle that down to the 950-1000 range if everything is right.

I'll say I'd put about 20-22 initial timing on it. That's where my 340 with a 528 mechanical wanted it.

---

Rebel and RobX, I am not sure how to set initial timing I guess. I thought initial timing had to be set below 1,000rpm and above that your distributor started to advance...I guess I may be wrong. If I am I could tell you what I have it set at tomorrow probably. IIRC I tried to set it at 23deg.

---

As long as it's not bleeding in mechanical advance at idle, you're setting initial. Don't worry about total at this point. Not sure why you are having trouble seeing it. Pretty easy unless you have a chrome damper or no marks to reference.

23 initial, if correct, is a decent starting point for that set up IMO.

If using a stock damper, hillbilly timing tape it.

---

Its a nice shiny SFI damper from Summit and it is kind of difficult to read. I will do it in the garage this afternoon and see what it says.

dartman366, how high do I need to have the rpms to make sure I am reading total timing and what should that number be?

10 o to go, my distributor is a factory electronic with vacuum advance, BUT I have the vacuum line blocked off.
When I rev it up it comes right back to 1,400rpm

---

Get it up to 3000rpm to set the total timing...34*
should be close for testing... then you can tweek
it in on the track.... if it drops right back to 1400
it sounds like its a mech issue... check the secondary
screw to see if its too high.... IF you want to pull
the carb off to set the transfer slot you can...
once its off flip it over(gas will pour out) and
look at the slot at the throttle blades....set the
throttle so that the slot makes a square hole...
if the blades are open too far you are past the idle
circuit so the idle mixture screws wont have any
effect... so get it down on the idle then mess with
the mixture and idle set screw...... you said that
the throttle cable has some slack so that MOST LIKELY
isnt the issue... check the secondary screw... timing
comes first though... then the carb

---

Mike you treed me, just talked to a fellow who had the same issue with a 950 and it ended up being the idle screw for the secondarys, mis adjusted and held the throttle plates open just a little too far, hopefully thats all it is, but Mike is correct.

Quote:

---

If you just freshened this carb I would check the gasket between the main body and base plate to make sure it's the right one. Sounds like you have the idle holes covered up.

---

Quote:

---

In would think with that cam you would want 36 degrees at 1400 rpms (total all in) bigger cams (and a 242 in a 340 is big enough) need lots of advance at idle to make them idle right. Yours will probably need 28 to 30 at 900 to idle right
Put the lightest springs you can find in the dizzy!

You can test it by advancing till you get a good idle set and check where that put you at in gear. The total will be way to far advanced but this is just a test to find where it needs to be to allow you to set your idle to keep it running nice then you will know how much faster it needs to advance to hold your idle!


I would think 900 to 1000 in gear would be acceptable idle with a bigger cam.

---

Quote:

---

The rear power valve should be blocked off,and the front should have a 6.5 power valve to start with.
Either you mixed them up,or possibly you swapped the metering blocks from front to rear.
The front metering block will have the mixture screws and power valve.
The jetting will have to be changed if you add power valves where they were not before.

Keith

---