the engine runs great at idle, low revs, 1500 - 2000. When in gear, runs ok if I dont punch it, up to about 2000 or so, then Vac dies, tach goes dead, and it stumbles like boulder going downhill. Could a voltage, low battery/ coil affect this?

thanks
scott

It could be your coil but usually an intermitten coil acts up with temperature not engine load. Sounds more like carburation to me. You can always buy a coil, try it, and if it doesn't work, take it back.

Good luck.

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Regards,
RLK
My Cars (http://home.texoma.net/~rknipe/)

Be careful though, some places do not take electrical parts back so don't get stuck with em..

Thanks! I can rev it till it stumbles, and then choke it with my hand and it does not get better, its worse. Stopped the secondaries, and It still get too much fuel. New Holley 450 carb.
Thanks

I have a BnB 350, sportsman 2 heads, Comp .50 cam, tunnel ram w matching twin -450 Holley carbs, headers w 2.5 inch exhaust to turbo mufflers, beefed up 350 tranny with 3500 stall, new driveshaft, posi rear end (orig). Trouble is in dialing it in so it transitions well. All carbs, manifolds, heads, shortblock, dist are new. Seems like the idle circuit on the carbs is fine, revs in park ok, pulls 10in vac at 850-900 revs. As I drive in first, I accelerate slowly to 1400 or so and then it starts "2-cycles" "stumbles", like the choke is stuck.. lol ( no choke, manual secondarys). About the same time, is when the vac drops, so I adjusted powervalves, etc. Checked float bowl positions, Timing set to 35-40 total. The engine has never been really dailed in right, or dyno'd, But it has run better. It did have an electrical short, alt wire melted part of wiring harness, etc. and I am tring to get it back to some form of running. Thats why I thought maybe coil shot. Thought maybe I flattened a cam or something... <scheese>, but they adjust well, vaccuum is steady at idle, got hyds, 1/4 turn from zero.

Anything I can try and /or check would be greatly appreciated.
Thanks, Scott