Thread: early '70's 350 stalls when put in gear

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Hi all

Early 70's 350 its in a C10 with a powerglide tranny.

I beleive the engine came out of a van as timing mark is at 7 o clock on the dampner. Timing is really close we put number one at TDC and made certain the dizzy pointed at one.

We just did a poor mans valve job, new head and intake gaskets.

Was told by previous owner it has a mild cam, although could not tell us what kind or type or any other info on it.

Has Edelbrock performer intake, and running a quadrajet carb with unknown background and is suspect.

Running block hugger headers open to colllectors (Exhaust not hooked up yet)

Runs smooth, sounds good at high idle.

It starts and runs but will stall if we dont keep it idling high, and stalls when we put it in gear.

Anything other than the carb I should be looking into?

Any help is much appreciated.

Thanks, Robb

Start with the basics.. beg, borrow, rent a timing light and set it (timing) to spec. ,

needs longer exhaust for idle

Originally Posted by 34_40

Start with the basics.. beg, borrow, rent a timing light and set it (timing) to spec. ,

I have a light, timing mark is at 7 o clock. The timing cover was replaced by a previous owner with a chrome unit with the regular timing tab.......Thats why I believe either the engine is from a van or dampner ring slid. I may have another dampner I could install....

Check for vacuum leak.

Originally Posted by Robbp

I have a light, timing mark is at 7 o clock. The timing cover was replaced by a previous owner with a chrome unit with the regular timing tab.......Thats why I believe either the engine is from a van or dampner ring slid. I may have another dampner I could install....

You can also measure the O.D. of the damper and get a piece of timing tape.. set #1 to top dead center and apply the tape with the "0" under your timing tab. And yes, look and listen for vacuum leaks.. Have you turned up the idle screw? Do you have a tach to know what RPM it's at now?

Originally Posted by 34_40

You can also measure the O.D. of the damper and get a piece of timing tape.. set #1 to top dead center and apply the tape with the "0" under your timing tab. And yes, look and listen for vacuum leaks.. Have you turned up the idle screw? Do you have a tach to know what RPM it's at now?

ok, didnt know about the tape ill look into that,,, turned idle screw in quite a bit to keep her running.
i ll look for vacuum leak too, yes i do have a tach i can throw on it... thanks

One thing about using the tape, it's only as accurate as you are at setting TDC compression stroke. If you're off on locating TDC then every timing setting from that point forward will be off. You need to get TDC dead accurate before sticking that tape in place. Close is not good enough.

This brings up a point I've often wondered: just how important is the almighty zero?

After all, the correct setting is only the start point, isn't it? Won't you be fudging it back and forth till you fond that sweet spot anyway? Does it really matter if the timing gun shows 26 degrees total advance, or 24- so long as the actual setting makes the most power?

Has any among us not set timing by ear, working on some project of ours or anothers, then took it down the road, adjusting by tiny increments until the seat of the pants peak power is achieved?

Now, I'm not trying to convince this guy It's not important, because I know it is. But that being said, just how critical is critical? I suppose it depends upon the motor- I've never worked on a top fuel drag car, and I think on the insane builds a degree can make a catastrophic difference. But on an old 350 with some recent top end work, seems to me he should get it running pretty well whether the mark is dead on or slightly off.

Anyway, just been pondering that point for a while now, thanks in advance.

doesn't matter where zero is---it only matters where the other 359 are-------------


But having said that---you do need a reference mark if you are diagnosing things---if this was a normal start up of a street rebuild, i'm sure most of us (well----a few anyway) could put this thing together and light it off and set carb and timing by ear/sound, seat of pants, does it kick the starter, run on after shutdown---------


However----you have a vehicle swap, a different timing cover, who knows what for carb to manifold fit, shorty open headers, quite possibly a sticking advance mecha nism--------------and maybe a faulty lock up converter??????????

The other 359!! Love it!!

As Jerry said, it has to be a known value (and repeatable) the OP needs a reference to come into spec. , does a degree or 2 amount to much for a daily driver? No.. but OP has to have a foundation to build on. Having done headgaskets, means the rockers are probably all out of adjustment too! I think Techinspector and or RSpears had a link or writeup that was worthy of a How-To.. He needs to download it and follow the instructions.

And imho a Vacuum Gauge is also a requirement when checking / adjusting lifter / carb / timing. I don't make a move on my car without it, even mounted one in the dash permanent!

Originally Posted by firebird77clone

This brings up a point I've often wondered: just how important is the almighty zero?

Just like anything you measure, the value you measure only means something if you have a known, repeatable reference point. If you're measuring a crank journal does it matter if you zero your micrometer before you measure? Timing's the same, and accuracy of your zero point (or of the other 359 marks) is pretty critical to anyone else that tries to make sense of that engine's settings at a later point. With today's crappy fuel and more exotic materials used in performance engines timing can be even more critical. For example, the hypereutectic pistons in my 347 came with a strong warning that total timing is not to exceed 36 degrees, which became the limiting factor in building the timing map for computer controlled spark advance. Other sources say that pushing total timing to 40 or more as you're pushing the rpm limit will squeeze out more power.

Does all of this apply to a near stock 350 SBC engine? It's not necessarily "critical", but like Jerry points out if you have ANY unknowns like timing cover, placement of the pointer, etc, etc, etc, then knowing your zero point is, to me, one of the basics of knowing what you've got. Anything less than dead right makes it a crapshoot.

I'd put my money on a vacuum leak. Intake or carb

guys thanks for the info, I agree in trying to find out the exact cause it would be sensable to have the timing buttoned up so we have a known setting.

I will continue to look into this and get it set right. meanwhile I will look for a vacuum leak and any other issues to get this truck running right. Its fricken 0-10 degrees here so I am fighting the cold as well as the issues with this engine. Anyways, THanks for the help.

Robb

You originally said open shorty headers----explain that ---- if you are trying to run a shorty style header with no pipe on it, you will find that it won't want to accerate off idle and other erraric symothes--------


Is your manifold/ gasket/ carb base compatible???????


many times I have found older gm type advance mechanisms sticky a nd won'r advance /retard correctly every time giving erratic behavior to engine--