[Shadetree55]

what's your idle speed??? Is the choke opening all the way?? What is timing set at?? Spark plug gap??

 

[Shadetree55]

I'd double check timing also just looking (only) at where #1 plug wire is on the cap & where the vacuum advance is pointing it would be worth rechecking timing.Vacuum line off & plugged I'd want at least 12* advance & if you have a timing light that can read total advance maybe 34-36* total then make sure your vacuum advance will add something like 10* when plugged in.while at idle if you have it connected to manifold vacuum or off idle with ported vacuum connection.Also if it's ported try switching to manifold vacuum.Maybe totally different issue but try one thing at a time.What is the cam specs? if not close to stock another thing could be the stall speed of the converter a real low stock stall speed converter might be dragging the engine down enough to die but shouldn't at 900 rpm.

#1 is in the position stock HEI should be so I suspect timing is off and curb idle may be too low also. Just my 2 pennies.

 

[Shadetree55]

I would suggest pulling #1 plug, bump it over and make sure you are on number 1 compression. then pull cap and see where the rotor is pointing. You may be off a tooth and able to run but not get enough advance on the distributor. That advance is way too near the carb .

 

[Shadetree55]

What does your rpms drop to in gear. Early in the post I asked the question concerning if you knew what stall speed your converter happened to be.Not that I would recommend changing it as long as you can & from your post have got it to now idle in gear. On a friend & customer's Elcamino I built a 350 with a mild cam he didn't like the way it clunked & drug the engine down when put in gear. I swapped the torque converter to one with 2200 RPM made a world of difference. In fact he had me do the same converter swap in a 65 Corvette I had put together a couple years earlier with the same results on his 400 turbo as the 350 turbo in the Elcamino.

I still think he has a timing issue. even though it looks to be a new carb could have issues there or a combo of both. His description doesn't indicate enough cam to be part of the problem. He could have a problem with that brake booster. He hasn't stated what the brakes feel like.

 

[Shadetree55]

I agree if it's a stock crate engine as indicated I be expecting something near 20" vacuum if it was mine I set timing at 12*initial & make sure I was getting around 10* more advance when plugging the vacuum advance into a manifold vacuum port on the carburetor.Then readjust carburetor mixture for the highest idle vacuum.Seems to be the popular opinion that vacuum advance needs to be ported but nearly all GM engines prior to around 1967 ran with the vacuum advance connected to manifold vacuum I still do that if possible but sometimes ported is the best way to go.Probably a lot of disagreement with that but it has worked well for me for many years for a couple different reasons.

I've always gone with ported vacuum. Of course most of mine have been extremely mild or stock builds and usually get away with around 10-12 degrees initial timing.