Stalling problem

[Dirka]

I did some readin through the archives and found a similar problem talked about, the only difference in the two were that my 77 stalls out once put into any gear.  Idles good but once gear it wants to stall out unless I feather the accelerator.  My fist step is going to do this:

     My first suggestion would be to check the incoming fuel filter.  My second guess would be something got into the jets on the carb.  Sounds like a fuel flow problem only because you said it worked great before and after changing out the intake and carb. and at idle it is fine and at w.o.t. it moves slow.
     Does the engine sound like it is starving for fuel when you are trying to drive it ?

I didn't know if anyone else might have a different idea? They guy I bought the truck from says it needs the valves to be reseated and this issue the truck is having bc of a vacuum issue, which also at low rpms inhibits the brakes working properly. Any truth to what he said? Before I take apart the topend, I like to see if there is any easier fix to this.
Thank you

[Fairlane514]

Put a vacuum gauge on it (full manifold) and see what it reads.  I assume you have a TH350 or 400, both have a vacuum modulator that could be bad causing a severe vacuum leak.

If the vales were not sealing it wouldn't idle very well either. Maybe he meant readjusting the valves?

What carburetor do you have?

Stock 350 motor?

Big camshaft? if so, may be you need a higher stall torque converter.

 

[Dirka]

TH350 yes.
He mentioned one or more of the valves were loose when he redid the bottom of the engine.
The carb is a Edelbrock 600cfm, model number unknown. see attached picture.
it's a 305 motor, for the most part I believe it's stock besides carburetor and he said it has a mild cam but no idea specs on it for duration and lift etc.

[bd]

What's your idle RPM?

[Dirka]

Idle rpm im not for sure I don't Have any of the necessary tools to do any of those checks, it does idle pretty rough though. Im a total newbie to this

[Fairlane514]

There are a lot of things to check before you take the top end off. 

I would adjust the valves and see if that helps smooth out the idle. Also use a vacuum gauge to see how much vacuum you have and if the needle is bouncing all over the place.

You may have a large vacuum leak somewhere. You can plug everything vacuum operated and see if that helps and then reintroduce one at a time until you find the problem.
When I say plug, use rubber plugs to cap off all ports on the carb and intake manifold.

Also check your timing.

[DnStClr]

AutoZone has vacuum diagrams online, and this is a link for the 77 350, so the 305 should be the same.

[Dirka]

Thank for you the diagram!
I will check on those vacuum lines tonight. I got ahold of a family friend who has the vacuum gauge and a timing light so hopefully between those we can get this figured out later this week.
Greatly appreciate the info!

[Dirka]

Another quick question,my truck is a 77 custom deluxe came with AC and a 400ci motor from factory, but it currrently has a 305 with a edelbrock 600cfm carburetor and new distributor (we think it's a PerTronix Flame Thrower)
When looking for the vacuum line diagram from autozone, should I looking at the 400 diagrams?

[DnStClr]

The emission controls will be similar for both engines but follow the 305 diagram.

[Dirka]

I adjusted the valves to specs I read on here on and now the truck won't start at all. We did try advancing the timing of the distributor and got it to run once, but the distributor was bottomed out counter clockwise against the firewall. Adjust the distributor a tooth or two over so it would sit straight on, and nothing again. Changed HEI units and still no start up. wondering if maybe the harmonic balancer/ timing might off when the previous owner installed a new, what I'm assuming is an RV cam. But then again why would it run before (with stalling issues talked about earlier) and now not after adjusting the valves?
Side not the one time we got it running, it sounded smooth and running like it should to, according the mechanic helping me.
Ideas??

Also the vacuum lines I have, are the PCV, one to the distributor and then to brakes. I don't have any of the EGR lines.

[Fairlane514]

The 305 balancer has the timing mark at the 12 O'clock position, and if your timing pointer on the timing cover is at the 2 O'clock position you will never see the timing mark on the balancer with your timing light.  You will either have to change the balancer or the timing pointer.
Bottomed out against the firewall counter clockwise on the distributor is retarded timing not advanced.

If you can determine you have the correct balancer and timing mark, I would start over with the distributor. Remove the cylinder number one (front drivers side) spark plug and turn the motor over (I like to do it by hand with a breaker bar) until you are TDC on the compression stroke (air will escape around your finger if you stick it in the spark plug hole). Then turn the motor over a little more until you are  10 degrees advanced on the balancer. Then stab the distributor so your rotor is pointed exactly at your number one terminal.  The motor should start and then you can set your timing with a light.

 Did you set your valves zero lash and then 1/4 to 1/2 turn?  Does it have roller rockers or original stamped? You may have the valves too tight.

[Dirka]

I did set the valves at zero lash and then a 1/2 turn. I have original rockers.

[454Man]

Try just a1/4 turn. You're valves may still be open. Also sounds like you need to pull the dizzy again and rotate the crank till cylinder #1 intake then exhaust rockers go up and down, then line the slot on the balancer up with the 0 on the timing mark. Find #1 on the dizzy and there you go. Easy ask cake

[Fairlane514]

Have you set valves before?   Zero lash is using your forefinger and thumb only, twisting the pushrod until you feel enough resistance (from tightening the rocker arm nut)   to stop the pushrod from twisting. Its a fairly light touch. Then 1/4 to 1/2 turn more. I also like 1/4 turn myself.