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post #21 of (permalink) Old 05-18-2009, 02:11 PM
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Hmm, good info.
I never thought about it before - that the side pivots would be superior. But I see your point. The center of the rounded float will "see" the average fuel level anyway, and the roundness keeps it more in balance. And the plus -- jet extensions and the inside vent extensions (whistle) would clear fine, eliminating the need for the notched center floats.
KISS!

The outside vent or "bridge" as we called it, made from copper tube or brake lines - always gave that custom look - I wonder why it took Holley so many years. It's not just good for off road, but road courses too.

The biggest problem, other than the carb itself malfunctioning or put together wrong, was guys putting a huge carb, like a 1180 on a small motor like a 283.

Sure would be nice if it was that easy to modify a FI - without getting into the computer and fuel mapping. That's a whole different world.

Last edited by RRich; 05-18-2009 at 02:13 PM.
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post #22 of (permalink) Old 05-18-2009, 03:21 PM
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Quote:
Originally Posted by RRich View Post
Hmm, good info.
I never thought about it before - that the side pivots would be superior. But I see your point. The center of the rounded float will "see" the average fuel level anyway, and the roundness keeps it more in balance. And the plus -- jet extensions and the inside vent extensions (whistle) would clear fine, eliminating the need for the notched center floats.
KISS!
Low RPM engines don't need the huge fuel flow tract of the Center Pivot float bowls either.
Unless you are SERIOUSLY RACING a big block for all it's worth,
The side pivot bowls are just fine!

With the added benefit of being better at off camber fuel metering,
AND,
They are MUCH easier to work with in regards to fuel lines, ect.

If you are going to take the float bowl off 40 times a weekend to change jets at a race track, the transfer tube can get quite annoying with side pivots,
But if you are only doing it ONCE or Twice to tune jets/power valve and then leaving it alone,
They ROCK!
----------------------------------------------------------

Quote:
The outside vent or "bridge" as we called it, made from copper tube or brake lines - always gave that custom look - I wonder why it took Holley so many years. It's not just good for off road, but road courses too.
I wore my hands RAW one summer making polished stainless steel versions of that raised vent line!
Made some GOOD MONEY from it, but I had a hand grip at the end of that summer that would crush about anything!

I first saw that on a farm truck when I was about 10 years old, around 1970, and I though it was a good idea.
The farmer was making his carb run when the truck was inclined to dump the load...
When it didn't have a dump bed!

Copper is MUCH easier to work with,
And if you have slash cut tubing inserts in your vents, you can use RUBBER FUEL LINE!
That REALLY makes it easier!
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Quote:
The biggest problem, other than the carb itself malfunctioning or put together wrong, was guys putting a huge carb, like a 1180 on a small motor like a 283.
YUP!
Don't know how many Holly Dominators I've seen installed on small blocks with the owner bitching about the engine not 'RUNNING RIGHT'!

Without getting into a long math equation that will lose about everyone reading this,
A 258 CID engine should need a carb around 240 to 290 CFM carb. (with a rough rev limit of 3,000 RPM)

A 304 V-8 with 4,500 RPM Rev limit should only need about 450/500 CFM.

A 360 with same 4,500 RPM rev limit should only need 500/550 CFM carb...

(math, so run now!
Engine displacement, Say 304,

304 CID 2 = 152 CID per Crankshaft Revolution (4 stroke engine)

152.0 CID X 0.85% Cylinder Volumetric Efficiency = 129.2 CuIn per Engine RPM.

129.2 Corrected CID X RPM Rev Limit of 4,500 RPM = 581,400 Corrected CID per RPM.

581,400 1728 (1 Cu.Ft.) = 336.45833 CuFt per Minute (CFM) Rounded to 336 CFM.

Add 100 CFM for over rev, free rev, and for faster RPM gain when loading the engine to maximum,
336 CFM + 100 = 436 CFM.

The closest 'Larger' carb sizes you are going to find is a 430, 450, 500.

Current production 4 barrel 'Off Road' carbs are 470 CFM, 670 CFM & 770 CFM models.

Current production 4 barrel 'Street' carbs are 390 CFM, 465 CFM, 600 CFM, and up...

Current two barrel carbs are 350 CFM and 500 CFM.
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Quote:
Sure would be nice if it was that easy to modify a FI - without getting into the computer and fuel mapping. That's a whole different world.
When I worked for DFI, we were working on a system that had sets of dials on it.
You chose one of 4 or one of 5 different RPM ranges,
And you richened up or leaned out the fuel mixture simply by turning the dial in the appropriate RPM range.

We were even looking into adding adjustments for load in those RPM ranges when Accel purchased the company and killed the project so it wouldn't compete with their versions.

We called it 'Fuel Injection For Dummies'...
And that was before the 'For Dummies' books were out,
this was back in about '84 or '85.
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