: I'm getting my "Screamin' Six" 1971
: Valiant ready for Columbus, and am trying to
: fix the only engine problem: At high rpm's
: (4000+), acceleration becomes
: surge,die,surge,die. If you keep your foot
: in it long enough, it'll get to 5000 rpm,
: but this will never make a good time in a /6
: race. I've been working on it today and
: doing some test runs. Holding it in second
: gear at WOT, the engine accelerates good to
: 4000, then just doesn't want to rev higher,
: except for the surge-die thing. After
: shifting to third, it continues to do it,
: only now at 3500 or so rpm.
:
: Today, I finally changed the secondary jetting
: in the 450 Holley. Went from a #9 metering
: plate to a #39. The equivalent of going from
: a #64 jet to #69, according to the Holley
: book at the auto parts store. I also pulled
: back the ignition timing, first from 33
: degrees to 30 (total), then to 27. Each
: change seemed to help a little, but it is
: still unacceptable.
:
: I wonder if it may be the big block fuel pump.
: It is a higher volume unit, but the outlet
: has a very small inside diameter, in the
: 3/16" to 1/4" range (?!?!?!). And
: it requires a 90 degree adapter to hook up
: the fuel line, which also has a small I.D.
: in it. I may try a new stock /6 fuel pump.
: Or maybe raise the float levels in the
: Holley a little above the ideal of fuel
: starting to come out of the holes.
:
: The spark plugs are at 32 now, and I'm using a
: NEW (NOS) electronic distributor, cap, and
: rotor. It has stock electronic ignition and
: a stock coil on it.
:
: I need to get this thing fixed in the next few
: days.

: I'm getting my "Screamin' Six" 1971
: Valiant ready for Columbus, and am trying to
: fix the only engine problem: At high rpm's
: (4000+), acceleration becomes
: surge,die,surge,die. If you keep your foot
: in it long enough, it'll get to 5000 rpm,
: but this will never make a good time in a /6
: race. I've been working on it today and
: doing some test runs. Holding it in second
: gear at WOT, the engine accelerates good to
: 4000, then just doesn't want to rev higher,
: except for the surge-die thing. After
: shifting to third, it continues to do it,
: only now at 3500 or so rpm.
:
: Today, I finally changed the secondary jetting
: in the 450 Holley. Went from a #9 metering
: plate to a #39. The equivalent of going from
: a #64 jet to #69, according to the Holley
: book at the auto parts store. I also pulled
: back the ignition timing, first from 33
: degrees to 30 (total), then to 27. Each
: change seemed to help a little, but it is
: still unacceptable.
:
: I wonder if it may be the big block fuel pump.
: It is a higher volume unit, but the outlet
: has a very small inside diameter, in the
: 3/16" to 1/4" range (?!?!?!). And
: it requires a 90 degree adapter to hook up
: the fuel line, which also has a small I.D.
: in it. I may try a new stock /6 fuel pump.
: Or maybe raise the float levels in the
: Holley a little above the ideal of fuel
: starting to come out of the holes.
:
: The spark plugs are at 32 now, and I'm using a
: NEW (NOS) electronic distributor, cap, and
: rotor. It has stock electronic ignition and
: a stock coil on it.
:
: I need to get this thing fixed in the next few
: days.

: It sounds like your running the float bowls
: dry. Check the sock in the tank and also
: make sure the fuel line is not partly
: clogged with rust. Does not have to be
: blocked, just restricted. Did you do the
: necessary modifications to the 440 pump?

: It sounds like your running the float bowls
: dry. Check the sock in the tank and also
: make sure the fuel line is not partly
: clogged with rust. Does not have to be
: blocked, just restricted. Did you do the
: necessary modifications to the 440 pump?

: I swapped the /6 arm into the 440 pump, but
: didn't do anything else to it. There was no
: free play in the pump stroke when I operated
: it by hand, so I don't think there's a
: problem with only getting a partial stroke.

: Tim,
:
: It may be a carb problem too. I had troubles
: like this on my Holley 4 bbl at one time.
: The secondaries were not opening fast enough
: because they are calibrated for a larger
: engine. You might try getting a quick-change
: sec. spring kit and see if that helps.
: Probably try a stock fuel pump too after you
: have checked the lines and such. I have run
: my slants to 14.30s consistent with a 600
: carb and stock (rebuild) pump.
:
: Lou

:
: I swapped the /6 arm into the 440 pump, but
: didn't do anything else to it. There was no
: free play in the pump stroke when I operated
: it by hand, so I don't think there's a
: problem with only getting a partial stroke.
: I have 3/8" fuel line and a 3/8"
: filter between the pump and carburetor. I'll
: try blowing out the line with an air
: compressor and see if it helps any. The car
: has a full (stock) gas tank in it now, so I
: need to run it down before I can pull out
: the fuel pickup. When I do, I'll cut off the
: sock filter and just use the one 3/8"
: filter. I don't think there's any line
: problems, but I'll check for kinks or other
: damage to it.
: I can run this engine at 3300-3500 rpm on the
: highway for miles at a time, and there's no
: problems. It's only when the 4 barrels open
: up that it draws too much fuel. When
: cruising around, the car seems to feel a
: little better with less ignition advance in
: it. Not a huge change, just a little one.