Here it is, a little long,

I am idling in park or Neutral at 1000 Rpms and 12 Inches of Vac. Drop it into gear and I lose about 300-400 RPMs and drop the Vac to 6-7 inches. It idles rough and I say it's because of the cam. However it is losing alot of power here and at time stall on me. I cleaned the carb up put a fuel pressure regulator on because without it is getting 9 PSI of fuel. I adjusted this to 6 and it is steady, the vac is steady, maybe a inch of play, maybe because of the cam. I checked everywhere for leaks and could not find any. Changed the plugs/wires/cap and rotor. All needed it. Seems to start and idle somewhat better, but still losing the power. Timing is strange, it has a Summit Harmonic balancer and when I pointed the roter at #1 the timing pointer was pointing above 40 degrees, looked like 45 degrees. Not sure if I understand this part. I have twisted it a little with a light and am coming up with 35 degrees at idle, this seems real high. Yes the Vac Adv is disconnected and I am using a dial light. At idle I turn the dial out to 35 and the ) degree hash on the balancer is hitting the tab when the light flashes. this seems very high, am I doing something wrtong here???

1969 GMC C1500, 350 4 Bolt Main, Brodix Track 1 Heads (131x221 Ports/2.02 Intake/1.60 & Stainless with triple springs
Chevy Crank with Stage II rods, Pistons are Flat Top, Holley 4150 Double Pumper with Mech Secondary’s (Jets are Stock), MSD Street Fire HEI Dist, Comp Cam 280H w/230 at 50,000 Duration and Crane Rollers, SFI Approved flywheel and Balancer, Balanced and Blue Printed Pete Jackson Gears, 350TH w/ B&M 3000 Stall Converter
True X-Pipe with Flowmasters, 3.73 Rear End w/Auburn Pro Lockers.  

Did you try richening up the idle alittle. Sounds like it may be alittle lean. When mine is in park it idles at about 13.2 AFR and when it is in gear it goes to mid to upper 14's. If I start with mid 14's AFR out of gear then put in gear it goes into the 16's and runs like yours. Is it a new carb. Has anyone turned any of the srews on it, if so you may want to turn both idle screws in all the way, then turn them both out the same amount. Maybe one turn each to start. Do the same thing one both screws, keep them even.  

Schum could be on the right track but I have to say something else about the combo...

Triple springs!!! Triple springs are dedicated to big and fast moving roller tappets. These will probably flatten a mild flat tappet cam in no time flat, pardon my pun.  

I did mess with the fuel air mixture screws. First let me say that it seemed awefully rich. So I tweaked the screws and it ran fine one day but terrible the next. So removed the carb and did a redneck cleaning of it, and swapped the 5.5 powervalve that was in it for a 3.5. I noticed the previous owner had a square bore spacer on a single plane open spreadbore intake. So I changed this to a square to speard bore spacer as well. I felt like I should have rebuilt the carb while I had it off. The fuel pressure I thought was flooding the engine also making it too rich, so that and the PV I though would lean it out some. I will tweak the screws again today. BTW what is AFR? The numbers I was looking at during this adjustment were VAC which is now set at 13inches in idle and drops to 8 inches in drive, but this is with what I consider a high idle screw setting of 1100 RPMs to prevent it from stalling when dropped into gear. Hope I am making sense. It does have triple springs, could you ellaborate on what your saying. Might I be looking at screwed cam???  

Idle rpm is really a function of the timing and how much air is getting in the engine though, your idle mixture is really set in the carb (as long as the float level is set correctly and the power valve isn't opening at idle). If there are no vacuum leaks and the primary blades aren't open too far (even though it sounds like they could be!) then your timing being high is probably contributing to your high idle. If your timing is really that high, it needs to come down! This engine probably only wants 35-38° total.

AFR stands for air to fuel ratio. Schum must have some pretty nice equipment (wide-band lambda sensor) to measure this accurately on his ride, it's something that should be known for tuning but many, many street carbs have been tuned decently without this information.

Flat tappet cams just don't need the heavy spring pressures that a triple spring makes. Short of max-effort solids, flat tappets are very rpm limited. There isn't sky-high rpm's that require the use of big spring pressures to keep everything in control. Using too much spring pressure increases the pressure at the lobe (and really adds stress everywhere in the valvetrain) and really accelerates wear on the lobe and lifter. You better find out what exactly those springs make for pressure. Who makes them? What diameter are they? What are they installed at? etcetera, etcetera...  

I have a Wide band O2 sensor that I also data log RPM, TPS, Vac, Fuel pressure and Tranny pressure. What carb (List#) and intake are you useing. You might be happier with a dual plan intake with your setup. My brother used one of those spacers and it felt like he lost 50 hp. I run a Comp XR282HR, RPM intake and 750 Demon. I get 12 in. Vac in park and 9 in. Vac in gear. My RPM drops from 900 to about 750.

GibTG has some valid concerns with your springs. You could do a compression test to see if things look OK. You could also take the carb off and flip it over and see where the throttle shafts are located in relationship to each other and also the transfer slot. A good place to start would be to set the rear shaft so you can just see the transfer slot (so it looks like a small square), then put it back on and try to set it up again.

Your PV will not affect your idle because it feeds from the main well, through the idle restricter (IR) to the idle well. It is the IR and the idle air bleed (IAB) that control the fuel that goes to the idle screws and the transfer slots. The 3.5 PV will only delay the fuel enrichment under heavier load. So you could most likely put the 6.5 back in it.  

well, i'm going to have to wait till the weekend to get some more done on this. I'm going to verify TDC with a piston stop and pull the distributer, making sure I have a solid reference for timing. While I'm doing this, I'll remove the left side valve cover, checking the valve opening and closing. There I'll get the spring info, so any advice for while I have this valve cover off in finding the spring info and or measuring the spring diameters would be great. I'll take plenty of pictures and hopefully get the timing specifics and possibly fixed. I'm not too happy about discovering a worn cam, but oh well. I wonder if this stall is pulling to much power from the motor when I drop into gear...Hmmm: Well one thing at a time. Thank you everyone.  

could you tell mne more about why you say the triple springs will effect the cam (280h). will it not handle the pressure generated by the triple springs. I'm going to have the valve covers off this weekend to determine the exact springs and establish a starting point for the timing (i.e. TDC) so I'm also looking for a good way of determining the spring diameter and type/model as well. what about these crane rollers, if they are designed to work with the triple springs than why not the cam or is it a quality issue with the cam. could I go to a different spring and if so what would be the recommendations from the crowd here.  

Shum, I swapped the PV because thinking that with a drop in vac I was getting too much fuel and flooding the system some when i dropped it into gear. This would not be so delayed if the vac drops as in my case. In my case I thought it was allowing too much to soon. The PV begins to open before it's rating and is then fully open at it's spec. 3.5 begins to open at say 5 or 6 inches. I have thought about the dual plane as I have seen some good running setups for the street with these. i need to look at the blades on the bottom again, your explanation helps, I need a picture to help me understand. I might pull this off again, so any more you can add in inspecting the underneath would be appreciated. I plan to take some pics. thank all  

Is your carb a 2 corner idle or a 4 corner idle. If it is a 2 corner idle you can drill the holes in the rear to let it feed fuel more evenly. When you have the carb off take the baseplate off. You will see two chanels running on the outside of the baseplate. At either end of this chanel will be the vertical passage for the idle. The front one will be drilled at the bottom of this vertical passage and the rear is not. Drill the rear the same as the front. Some times they block the outside chanels (like on a 4 corner idle) if it is you will need to open it up also.When you have it off you could also spray carb cleaner in the air bleeds and clean then out. Check to see if they are plugged. Also check the idle restricters in the metering block. You can get a pin drill set from a hobby store. Use them to see if any of the bleeds are plugged. Use the smooth end not the end you drill with. You don't want to make them bigger.