JUST GETTING THIS SMALL BLOCK RUNNING FOR MY SON'S CAMARO, 355 W/VORTEC HEADS, 270 COMP ROLLER,
ETC.CAR IDLES FINE UNTIL YOU PULL IT IN DRIVE, IDLES FOR A FEW SECONDS STARTS LUGGING DOWN, YOU CAN WATCH THE TIME RETARD ITSELF UNTIL ENGINE STALLS OR YOU MANUALLY RAISE IDLE. IT HAS A 2400
STALL CONVERTER SO IT SHOULD IDLE IN GEAR FINE.
THE DIST. IS BRAND NEW H/P HEI UNIT FROM ENGINE WORKS, ANYBODY PLAYED WITH SPRING AND SUCH FOR A PROBLEM LIKE THIS. I TRIED RUNNING THE VACUME ADVANCE TO INTAKE VACUME, HELPED BUT PROBLEM STILL
THERE, THANKS GUYS ROB...

You might be better off limiting vacuum advance and increasing initial to compensate. If that's the case, be sure and limit the mechanical accordingly.

What is your advance curve like? What weights and springs are you using?

AS FAR AS I KNOW, FROM A SPEC SHEET, IT HAS 24 DEG. MEC. ABOUT 10 VACUME, I KNOW I NEED TO RUN ABOUT 34 TOTAL, SO I AM GOING TO HAVE TO LIMIT THE AMOUNT AS I WAS JUST TOLD IN AN EARLIER POST
THANKS, ROB...

Rob - it sounds like your idling on the curve. A typical stock dist from '69 will have the curve start around 900rpm. That means any rpm from 0-900 the timing can't change because the weights need more than 900 rpm to put them in motion. If your curve starts lower than the idle you'll see the timing bounce up and down and the idle will surge up and down along with it. It may even be fine in neutral and when placed in drive the rpm drop also drops the timing and you get the problem you described. What rpm do you idle at? in drive? in neutral? If it's above 900 in neutral try to get it down to 800 or less and then reset your timing. It it's already below 900rpm swap in 1 heavier dist weight spring and see if things settle down.

I have a comp 280 hyd roller .224@050 in a 383ci mill and it idles fine at 700 in neutral and in drive drops to just below 600. You should be able to idle around the same place with your cam...

try disconecting the vacume advance entirely, then put one light spring in and one medium, set your initial at 12 or 14 degrees and give her a try. Fine tune from there, you will also need to reset your carb during the timing curve changes. Bob

OK GUYS GOT IT FIXED, ELIMINATED VACUME ADVANCE, SET TOTAL @ 34, RUNS GOOD, STILL SOME TWEEKING BUT WERE CLOSE, THANKS AGAIN ROB...

Mine did the same thing when I had the vac adv hooked to manifold vac.. Moved it to ported vac. and solved that problem. Ported vac should not have any vac on it at idle. Ported vac. on a Holley is on the side of the metering block. Not sure where it is on the QJ/carter carbs. A 270 isn't that big and shouldn't have vac problems.
Like DJD said, you probably need one medium spring to stop the adv from coming in so early.