Thanks Steve,
I was about to wade into this with a similar observation. I actually ran a
600cfm four barrel for four years on an almost stock motor (exhaust, cam
etc) , with a single plane intake, no less. I ran the original carb, then
a 500cfm holley 2 barrel, then Edelbrock 600cfm vacuum secondary: the
"overcarburated" four barrel ran the best of the four. I'm sure the four
barrels didn't get pulled open too often (until I used nitrous), but I had
less bog than the 500. Even a big (vacuum secondary) four barrel carb will
respond better than an average two barrel, as the primaries will be
smaller. It will only bog if the secondaries open prematurely (or too
suddenly). A 465cfm four barrel is probably a perfect compromise.
I still have the same carb on my 345hp balanced and blueprinted nitrous
injected 302, so obviously it wasn't NEEDED on the 260 but it wasn't a
problem.
Michael
Joey,
Please ignore advise against a 4 barrel on a 260 in favor of advice from
someone who has actually done it....(snip)
The performance is crisp, fast, and smooth. Some minor tuning... (snip)
... The larger one (600
CFM) suffers from flat spots and other signs of over-carburetting, even
on a 289. If you go all out with head, valves and cam, to improve
breathing, you might get the 600 to perform as smoothly and crisply as
the 465, and at higher power levels. Save up your money, if you want
this.
It is true that the engine runs out of steam at about 4800 rpm, but this
is a stock camshaft, valves and valve spring issue, not a manifold of
carb problem. This set-up, as confirmed by Edelbrock, is good to 6,000
rpm - providing the rest of the engine is.
Steve
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