Low RPM (vacuum?), High load bogging

[Shaggy]

I would run 2.5 on the exhuast i would also recomend larger then a 600 especially if you are going to a carter/edelbrock. My first car awas a 2-V Torino stock except for i put the bigger 4-V valves in it and was running the Holley street dominator intake and I had a 750 Holley on it. It would do the classic over carbed bog it i floored it at anything under 1500 (that was with some adjustments when i first put it on it would spit back at anything under around 3000) but i was willing to live with it because of the nads it gave me up high with the stock cam I was shifting at around 7000 (valve float for me was at 7200) now I was young and stoopid at the time but realisticlly i would still carry it to 6500 if i still had it becasue it was still pulling tlike a frieght train even up that high. Also found this on a Pantera board this is how that guy took care of it. Also his is a DPP not a vacumn sec but hope it helps

> I had a very similar set of symptoms with my 750 dp - though
> probably less extreme than yours. Throttle roll in was fine but
> sudden WOT would produce a very noticable stumble. After chasing
> accel pump cams, squirters, and power valves for about 6 months, I
> finally decided that it must be the jets (doh!). I'd gotten
> fooled into thinking it wasn't the jets because my plugs were nice
> and tan after track events with lots of WOT. Eventually I decided
> my primary mixture must be too lean, so I richened up the
> primaries by 4 sizes (up to 70) and to maintain the overall
> mixture I dropped the secondaries by 2 (to 76). The stumble
> disappeared completely.
>
> But maybe the point should be that for a novice carb tuner, the
> symptoms can be very confusing. Eventually, I learned a couple of
> things from my various tuning dead-ends: 1) don't change more than
> one thing at a time, no matter how tempting it might be (the
> carb's all apart, right?), and 2) make the adjustment jump large
> enough that you will know whether you made things better or worse -
> it's not always obvious. You can always back-up by half the
> original adjustment if you need too. Eventually you'll get there.
>
> Also, most of the off-the-shelf Holley rebuild books have a table
> in the back that tells what jets etc. were in the carb when new.
> That should give you a rough starting point for setting it up.
> You just need the Holley list number off the choke horn (3779-3,
> or something like that).
>
> Just for reference, I have a pink primary pump cam and and a white
> secondary cam with 28 (p) and 32 (s) nozzles.