Hello all, Im new to this forum stuff. I have a 67 pontiac tempest 326 originally a 2bbl. swapped the intake from a 1968 400 (obviously 4 bbl) and was using a Quadrajet from a parts pile laying around my Dad's old shop (somebody marked good on it with a sharpie so i figure hmm... must be good) slapped that bad boy on there, it ran well only after warm, when cold it would stumble fart or stall with moderate to heavy acceleration the choke was non functional due to the compatability between the 68 manifold and the unknown year B.O.P. carb (choke stat was in the manifold god only knew what the hell crazy things i needed to make it work as factory intended) anyhow this crap is pretty irrelivent to my problem that i face now..
   
       Giving up on this choke problem and deciding on an Edelbrock 1406 and adapter plate(600 cfm electric choke) to at least solve my cold drivabilty problems I found the car definately ran better cold with the new carb, however car feels significantly less powerful (didnt expect 100 hp from the swap but certainly wasnt looking to lose) I hooked the vaccuum advance to the manifold vaccuum port on the carb because that is where i had it hooked on the q-jet to help my hesitation problem and it worked well on the q jet(dont recall where I had the distributor set at but it seemed to work good well on moderate just felt a pretty significant loss in the top end after the I replaced the carb tried screwing around with several configurations ranging from timed vaccuum with the considaration of total advance (at 2500rpm had 36 degrees but 0 initial at 900rpm backfires out the carb on sudden acceleration from a stop) manifold vaccuum hooked up it and re-set it to a total of (34 degrees at 2500 and 12 at 900 vaccuum hooked up just all around a slug) bout the only thing I havent tried is no vaccuum advance at all I tried it while tuning and came to possibly a premature conclusion that the initial timing would be too high if i set it at a desirable total advance, am I paying too much attention to this total advance thing or does everything i touch just turn to crap and I should just live with a powerloss for drivability sake?

Please help!!
ps sorry for the run-on story just wanted to give backround to this nightmare im having

Thanx
SK  

well man, most as in like 95% of all Q-Jets flow about 750cfm, then you went down to a 600cfm...if it was running good with the q-jet (aside from the cold start thing) then you went to the edelbrock and lost some top end, it kinda sounds to me the carb is a little small...try another 700 or 750, thats what i would do.  

Don't know too much about Poncho SB's, but the above poster is right, a Quadrajunk does flow close to 750 cfm, and the 1406 is only 600 cfm. That may reduce your top end, but it can improve atomization in low end, street driven vehicles. Edelbrock's 1400 series Performer carbs are nothing more than the carter AFB carb with a chrome paintjob. They are very good carb's and easy to calibrate or adjust. The 600 CFM 1406 is applicable up to engines with 350 ci of displacement. So you are borderline. I doubt everything you touch turns to crap. You can buy calibration jets and metering rods in complete sets or speificly for your model of carb. I have a 1406 on my 267 chevy and that engine pulls like a train off the line, not too good in top end, but the carb is too big and I have to run 14 degrees inital advance, with manifold vacuum hooked up. I also have leaned out my secondaries to .086 jets and I'm currently running .092 primary with a .070 X .047 rod, I think. It's leaned out 12% in cruise mode, and 2% in powermode. Check your manual for the list of calibration points, you may need to changes rods and jets. I have no idea what my total advance is or at what RPM, just set my timing by idle quality at lowest idle speed setting, and drivability. You most likely have a THM-350 trans, and you'll know when you have everything set right, cuz no matter what your throttle position, it'll shift smoothly and you'll barely feel it.  

thanx for the tip, I suppose I'll try going into jets/metering rods n such, reading the plugs doesnt look to be excessively lean or rich I would say they actually look text book good (doesnt necessarly mean its optimal for top performance. according to edelbrock's theory on carb selection i am technically "overcarburated" by approx 100 cfm however it seemed to work fine on my 78 phoenix with a 305 super low compresson engine (also converted to a 4 barrel) using a crappy factory smogger manifold, however thinking about it as im typing thats comparing the performance of a 2 barrel rochester to a 4 barrel AFB (anything would have improved the stock setup) whereas im now comparing two different 4 barrel carbs with 2 completely different configurations. However today I just had to swap out my 10 day old 1406 for another brand new one (the shaft that runs through for the secondarys was leaking both in and out the carb credit to dealing with the local speed shop to make it a process of minutes to get a replacement in hand. consequently I started messing with the timing aspect again got pissed and stopped for the day before making that first post. probably a calibration kit, fresh plugs (for easier reading sake), maybe a curve kit, and some time at the local test and tune would probably give me the best idea on what the hell to do with it. also remembering that its a 326 not a 400 might help too lol, still I'm curious what this thing can do with the correct tuning and combo of parts worse case if I blow it up I have a 455 under a workbench problem is the stack of cash needed isnt there to build it just yet.. some day... some day....
Thanx for the advice. Hopefully I can post some good news after this  

Good news, unplugging the vacuum advance & setting the timing to 34 degrees @ 2500rpm leaving me with an initial timing of 13 @ 900rpm and its running awesome doesnt idle as smooth but not terrible, no pings but am gonna check the plugs tomorrow (yes I plugged the manifold vacuum port lol) I fiddled with the idle mixture, possibly not enough I was anxious to test it. I think i learned from this that the variable of the manifold vacuum port had lots to do with the accuracy of my total and initial readings and thats why unless one is a rocket scientist it is virtually impossible to predict what kinda effect its going to have at various rpm and throttle position in a real driving situation. Centrifugal advance pretty much will never lie, and ported vacuum is far more predictable and if adjustable can fine tune what cant be done with a centrifugal curve kit no track results yet however it would be awesome if the Magazine did an article on this subject comparing different results of ignition timing advance configurations and settings on a particular engine. I got to get a baseline then im totally screwing with the carb to see what more i could squeeze from grannys little 326. think i got this one solved and learned alot from it or at least i think lol.
Thanx for the input
SK  

good deal man, peace  

Anytime you need help,just ask, alot of these guys are way better at this than me, so if I don't know they will. I'd like to see an article as well, always reading about chevy crate 350's get pretty boring after like say 8 or 9 articles of it in the same mag. I'd love to see 305, 307 olds, even the rare and junky chevy 262, that was only produced for 2 years, and had no interchangeable parts with any other chevy SB. I'd like to see the sencond gen 4.3 LT V-8 built. Just to see what you can get from these "useless" powerplants. Of course fact remains, performance mags sell, cuz they put articles in there with 900 HP vehicles. Sales is what keep the printing presses rolling, so it isn't likely that your 326, will get much notice. I would do an article on it, but I'm not uch of an author, just long winded.