Thanks to everyone who sent recommendations for a replacement for my
single-points distributor. I ended up choosing the Mallory dual-point version,
with vacuum advance. Here are my current problems:
(1) The engine runs fairly well (as well as it used to) without the vacuum
advance connected. When I connect the vacuum advance, any opening of the
throttle produces a cyclic "surge" phenomenon, which consists of the engine
cycling up and down in speed. (I didn't try to drive it that way, only blipped
the throttle.)
Is the vacuum advance adjustable? Perhaps I am just getting too weak a vacuum
signal? Which brings me to:
(2) I only get about 13 psi vacuum (steady) at idle. I have done the usual
squirting of carb cleaner to try and find vacuum leaks and got no improvement.
My timing is not late; if anything, I have it set a bit early. The cam specs
are:
Isky 621262, Hydraulic 0.445" lift, 262 deg advertised duration,
208 deg duration @ 0.050
I have heard I should have 17-22 psi vacuum; what am I doing wrong?
(3) In general, I am not pleased with acceleration. WOT accel is not too bad,
but part-throttle is usually unacceptable. Even with wide-open-throttle, there
is usually somewhat of a bog at the beginning, until the RPMs get high enough.
Am I operating below my best torque range? Some more pertinent data is:
Vehicle: 1963 Olds F-85 wagon, approximately 3000 lbs, I think.
Compression Ratio: 9.0 to 9.5 to 1
Axle Ratio: 3.36
Transmission: F-85 Hydra-matic
Carburetor: Holley 4160 (vacuum secondaries), 390 cfm.
With regard to the carb, I have (somewhat systematically) varied the
accelerator pump cam and squirter size, and the secondary spring, ending up
pretty much with the out-of-the-box combination (i.e., every change made things
worse or the same). Perhaps the Holley is not the way to go; if not, what's
the right answer for this engine/vehicle combo?
Thanks in advance for your assistance,
Paul Erlandson
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