I have a really quick question and I'll bet the answer is super simple (I just can't seem to figure it out for some reason)

I just redid my 350, changed cam, pistons and stuff...
Anyhow, I can get it to idle in park fine but the lowest it will idle is around 1,200 rpm ...as soon as I put it gear, it stalls out!
I "can" get it to run in gear but I have to give it gas and when I make the shift from park to drive it squawks the tires.

What gives ??? I've tried advancing and retarding a few degrees but it didn't help. Maybe I should try the idle mixture screws? But I don't wanna make the problem worse (and I don't really know how to do it ;)

Any suggestions?

Idle mixture screws is a good place to start, richen the mixture and it will idle if all else is right.

1/2 turn out on each screw.

How much did you go up in cam and compression if any?

I'm wondering if the stall converter needs to be upgraded. Sounds like the tranny is dragging the engine below its idle point. The cam I'm installing recomends a 2400 stall.

What is the initial timing, what cam specs, etc. ?

mines doing the same thing. Its idleing at 1500rpms and when I put it in gear it either wants to go real bad or itll idle down and eventually die. If I try to idle it down out of gear itll idle fine then slowly idle way down and die.

Do you have your advance hooked to ported vacuum? Sounds like the throttle blades are too far open giving you addl advance. When you drop it into gear, the RPM's come down, reducing vacuum and ign advance and it slowly deteriates till it dies. Try unhooking your vacuum advance and see if it acts different. You shouldn't have any vacuum advance at idle if you are on ported vacuum. If you do, you need figure out why.

You could have too little initial timing causing you to have to increase your idle setting (open the throttle blades) to keep the car running thus starting to develop ported vacuum as well. If this is the case, you have to correct this before you will get things to work right.

I hope my rambling makes sense.....

do a flash test on your converter to make sure that the sprag is ok...

First, I would check for a vacuum leak, if you don't have one then check your initial timing in gear. I recently had the same problem and it was because I had the two lightest springs installed in my distributor. When setting the initial timing the light springs were letting the centrifical (sp?) timing to come in as well, then when the car was put in gear and the rpms would be knocked down I would lose all that centifical timing and have practically no initial timing to keep the engine running.

I think Troy and redneck are on the right track and that the loss of advance could be a major part of your problem. With a 1200 rpm idle you are probably getting some centrifugal that is going away when you put it in gear and the r's drop. Also, like Troy said, if you're getting vacuum advance at idle in neutral you'll lose some of it with the rpm drop when you put it in gear. End result is you don't have enough advance at idle in gear, which in turn results in enough power to overcome the converter's resistance. If it won't idle in neutral below 1200 you probably have a very big cam (or something is very wrong elsewhere). Big cams need lots of initial advance to (partially) compensate for the loss of velocity in the intake tract (poorer fuel/air mixing)as well as the larger amount exhaust gas reversion that results. Before we can give any specific advice we'll need some more specific info about your car. Timing specs? (initial?, total?, what rpm? vacuum advance? if so, which canister?) Cam specs? Intake and carb? Converter specs?

I think Troy and redneck are on the right track and that the loss of advance could be a major part of your problem. With a 1200 rpm idle you are probably getting some centrifugal that is going away when you put it in gear and the r's drop. Also, like Troy said, if you're getting vacuum advance at idle in neutral you'll lose some of it with the rpm drop when you put it in gear. End result is you don't have enough advance at idle in gear, which in turn results in enough power to overcome the converter's resistance. If it won't idle in neutral below 1200 you probably have a very big cam (or something is very wrong elsewhere). Big cams need lots of initial advance to (partially) compensate for the loss of velocity in the intake tract (poorer fuel/air mixing)as well as the larger amount exhaust gas reversion that results. Before we can give any specific advice we'll need some more specific info about your car. Timing specs? (initial?, total?, what rpm? vacuum advance? if so, which canister?) Cam specs? Intake and carb? Converter specs?

What Jerry said.
Any mech adv at idle out of gear goes away when you put it in gear. RPM varies with advance. Same thing for vacuum....hook it to ported, or unhook it altogether to trouble shoot this.
It goes like this......timing at 1200 idle is X, put it in gear the idle drops, along with the timing, the idle drops some more and the thing dies.
The problem worsens dramatically if the power valve opens with the loss of vacuum when you put it in gear. IE it will go dead rich.
A looser converter helps, but you will still need to get the rest right.
Good luck
Ron

Wow...thanks for all the replys. I'm glad to see I'm not the only person who's had this problem.
I didn't have much time to play around with the engine lastnight, but I did try setting the timing at around 14-16 deg. (I don't have a dialback light so I had to make an educated guess since the tab ends at 12 deg.) I noticed that when I had the "plug" on my carb and vaccuum advance disconected that the drop in rpms was less than before... So I'm definitely on the right track :D

When I adjust the idle mixture screws out should they all be the same? (4 corner idle) Because right now my fronts are both at 3 turns out from the seated position but my secondaries are only 1 turn out...thats wrong, right?

BTW my cam is the XE 294H (250/256 @.05 .519/.523 lift) 750 AED Carb, 10:1 CR. I'm using the vaccuum advance connected to the upper passenger side of the carb (guess thats ported)...My current timing is between 14-16 degrees initial and I'm idling in Park at around 1,100 RPM, in gear it's dropping to around 400 - 500 RPM

Wow...thanks for all the replys. I'm glad to see I'm not the only person who's had this problem.

Isn't that a great feeling! Sometimes I feel like such a dumb @ss for having these problems until I realize that most of the other guys have gone thru it as well. Anyway, what I did was have my wife put the car in gear while I checked the timing, I had about 2 to 4 degrees of advance in gear so I knew right then where the problem was.

That's a pretty healthy cam as well, I wouldn't be scared to run 20* initial to make it idle nice in gear, just make sure your total timing doesn't exceed 36* to 38* and you shouldn't have a detenation problem but check your plugs as a fail safe. Good luck.

how do you guys check your timing when is that high? When I have the gun and checking my intial its all the way under the water pump and the little timing tab only goes to like 16

Dial back timing light or full digital.

how do you guys check your timing when is that high? When I have the gun and checking my intial its all the way under the water pump and the little timing tab only goes to like 16


Get some timing tape, and mark your balancer accordingly to the right of the TDC mark, and then use 0 on your timing tab as your reference point.

Sapper, maybe I missed this earlier, but have you tried full time vacuum instead of ported? I have never had an engine with a big cam work well with ported vacuum. My experience has been with big blocks, but I cant see where that would change too much.

My combo 407BB .540/.540 lift 286/296 duration cam 9.8:1 compression
3000 stall convertor with th400 tranny 780cfm holly MS

My Intial Timing is at about 16*and total timing is under the water pump. My brothers got a dial back timing light that im gonna see if I can barrow it to check my timing right on.

Sapper, maybe I missed this earlier, but have you tried full time vacuum instead of ported? I have never had an engine with a big cam work well with ported vacuum. My experience has been with big blocks, but I cant see where that would change too much.

No actually I haven't tried full vacuum...will do though !

I've been working on it quite a bit lately, seems like it may have been a few things combined since I made a variety of adjustments....and found out that I was low on tranny fluid :P

I'm limited to the ammount that I can run the engine really, since I have no exhaust (very loud and I live in a pretty quiet community)
So far idle mixture screws, timing and fluids have been checked and I'm now idling at 1,000 to 1,100 and it will drop to 400 rpm in gear IT'S GETTING BETTER :)

A little more tuning and I should be able to get it almost "normal". I think some of the problem is that I'm running a 700r4 with a stock Torque converter and the cam calls for a 3200+ RPM Converter

BUT MAN DOES MY LITTLE VEGA ROCK & ROLL!!!!!!

What Jerry said.
Any mech adv at idle out of gear goes away when you put it in gear. RPM varies with advance. Same thing for vacuum....hook it to ported, or unhook it altogether to trouble shoot this.
It goes like this......timing at 1200 idle is X, put it in gear the idle drops, along with the timing, the idle drops some more and the thing dies.
The problem worsens dramatically if the power valve opens with the loss of vacuum when you put it in gear. IE it will go dead rich.
A looser converter helps, but you will still need to get the rest right.
Good luck
Ron

Ditto with Ron said. Happens far too often with big cams.

Sapper,

I just went through what you are experiencing, and with the right timing, and idle enrichment as Bob West pointed out, it should clear up. That is what I had to do.

Set your timing, set your carb float level, and the idle mixture to highest vacuum. Then reset your idle if needed.

having the same problem with sons car. He just rebuilt top end. Using a Voodoo cam 284/292 lift 525/546 110LSA, 1 3/4 headers. Also using a fuel regulator - set at about 7. sportsman 2 heads, performer RPM intake with a 750 carb. Choak disconected. Init timing set at 16, and 36 at 2500. Idels fine at 1200 or so but dies when put in drive. other then that it runs great ! Tranny is a 700r and I am pretty sure that converter it a little more then stock. we have tried to adjust carb and also checked with VAc advance disconected. distrib is an HEI. could use some help regarding the carb and exactley how to adjust. we also checked timing with car in drive and it was still at about 16. read all the posts here and can use any advise.

could it be the distributor? havent repalced any parts in it yet. Also some one mentioned about vac at idel. When we discounected the advance vac you could feel a suction from the carb at idel. which carb port would be ported vs non ported.

KC, vacuum readings? Neutral and in gear? Wonder if the power valve is opening, which ordinarily wont flow fuel through the booster, but at 1200 rpm it would try.