Low RPM (vacuum?), High load bogging

[hobgoblin351]

Hey Tom, if the cam is not a radical grind, then you're probably not going to rev up over 6000RPM anyway. So everything i was going to add dosent apply. You are right for getting rid of the 2 inch exhaust though. you're choking the enigne. I still say that with a mild cam and 2v heads the 2.25 pipe is the way to go, what did the shop reccomend? But then 2.5's do sound nice! lol Thats what I'm running, but then I'm flowing alot more air than you are at this point. Listen to alot of mufflers also. There is nothing better than that low rumble when you pull up to the light. Dont be so fast to trade in that Holley. Remember 2V heads dont flow at low RPM's so changing to an Edelbrok might not help it anyway.

[Metal396]

Well somethings up with the carb, i would before with the 2 bbl, hold the brakes lightly and hit the gas and it would push. With the holley it just dies and/or backfires through the carb. Edelbrocks are much easier to tune, already from reading their website i know how to tune em. Plus i have several friends that ABSOLUTELY LOVE THEM. Alot better for daily driving too, so it seems to be the way to go.

I havent had any suggestions from the muffler shop, but from other peoples oppinions 2.5s seem like the way to go. But we'll see. I havent heard many different mufflers, cant really find any good sound files online. I heard flowmasters quite a bit and i like em.

[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.