[Cliff R]

"The 850 CFM Edelbrock carb flows more that an SD-455 carb on my flow bench."

The Edelbrock 1910 is a copy of a 1980 Chevy truck carburetor part number 17080213. They set the full open angle of the secondary air flaps to open further and put two large round holes in them and bent up two taps and the trailing edge of them as well. It got a richer idle calibration but otherwise that's what it is, a copy of a Chevy truck carb.

The 1903-1906's and the exact same carb with the open angle of the flaps set to less distance. Edelbrock rated those at 795cfm which is probably about right.

I had several carburetors flow tested when I wrote the Q-jet book.

A 1969 RAIV carburetor was right at 750cfm.

A 1971 HO 455 carb 827cfm.

All the larger castings tested flowed right at 850cfm when set up in the same manner as the 1910's but no holes drilled in the plates or tabs added to them.

Removing the outer booster ring from a late model "800" cfm carb and using the same open angle as an Edelbrock 1910 we got 897cfm.

NONE of the carbs were touched anyplace with a grinder or sanding roll. I adjusted the full open angle of all throttle plates to exactly 90 degrees. The secondary throttle plate angle was also adjustable by grinding down the stop and adding an adjustmemt screw. That's how I came up with the dimensions in my book to set them. There is a poinit of no return with that deal and even worse when you go to far you start blocking fuel flow from the nozzles.

I also did some dyno and drag strip testing with several of them.

On a 455 with Edelbrock round port heads and RAIV camshaft the 1969 RAIV carb was down about 12hp to my 1977 Pontiac carb set to flow 850cfm. The power numbers were exactly the same thru 4500rpm's, from there on up the big 455 liked the 850cfm carb better.

At the track I tested the 750cfm Ram Air carb back to back against the 1971 455 HO carb and the 1977 Pontiac carb. Remarkably they ran very close in both ET and MPH. The 1971 HO carb for some reason ran more MPH than the larger 850cfm carburetor but we are talking about ..2-.3 so it may have just liked the tune on that one a tad better instead of the added airflow from the larger carburetor. The smaller 750cfm Ram Air carb was nearly as quick as the larger carburetors running within .03-.04 iin ET and giving up less than 1mph on top end.

At first that suprised me until you think about where ET is made at the track and the fact that the engine spends very little rime right up at the shift point in each gear especially if your car has a really tight/efficient converter and rear gears more suited to street driving that drag racing.

I've done a LOT more direct testing and mentioned some of it over the years on this Forum.

My 1977 Pontiac Q-jet which has never had a grinder or sanding roll touch it has NEVER once been outran by a Holley, Holley clone, or an Edelbrock AFB or AVS clone at any power level unless it was on a single plane intake WITHOUT a spacer on it. SIngle plane intakes don't like the huge secondary throttle plates from a spread bore carb sticking deep into the plenum areas. They aren't really all that happy with a square flange carb bolted directly to them and why I ALWAYS use at least a 1" spacer on a single plane intake, no exceptions.

I did some of that testing with witnesses and documented for the Popular Hot Rodding Engine Masters articles back in 2004. They folks writing the articles asked for the testing on the dyno and we carried the big Holley carbs to the track and the Q-jet outran them there as well. Of course you aren't seeing all that in print, one of my early lessons with that sort of thing.

I will mention that right after writing my book I gained a LOT of attention from the magazines and was asked to contribute. However they ended up NOT liking my carburetor, distributor and camshaft testing so very quickly brushed me under the rug. With that sort of thing you are NOT allowed to make MORE power than a "high performance" aftermarket part or you'll very quickly fall out of their graces. That's just the way it is with that sort of thing. I discussed this recently with Lars (the Corvette guy) and his testing with carburetors, distributors and such mimics my results almost exactly. I found it both remarkable and interesting that two dedicated tuners and carburetor builders from completley DIFFERENT backgrounds working 100 percent independent from each other came up with the same conclusions when it comes to these things........FWIW.......