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Old 05-23-2022, 10:18 PM
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Tom Vaught Tom Vaught is offline
Boost Engineer
Join Date: Dec 2001
Location: The United States of America
Posts: 30,843

From the speed-talk thread.

Simply stated, the guys are spot on, a 950 (from Holley) is a 750 HP series (shaped entry) body with a 850 base.

A 1000+ is an 850 with HP (shaped entry) body.

I run a 1000+ vacuum secondary HP on my 489 cid motor (all street, 1000 rpm idle, and cruises at 1600 rpm in 5th gear on the highway), and I actually swapped an 850 billet base from BG after an unfortunate bench accident :roll: It is dimensionally the same and runs very well

I also ran mine on my car when it was 434 cid as well, I consider it a very good match for street/strip 400+ inch motor, I actually got 13 mpg on a 5 hr trip with a 4 speed, 3.70's, that carb, and the 434 FE with a 250@.050 solid flat tappet and a single plane intake from Vegas to Bishop CA and back

I got a deal on the vac sec, or I probably would have went double pumper though. Holley seems to agree because they dont make this carb anymore LOL however, you can buy an 850 vac sec with a shaped air horn from BG or QFT.

Apparently GTO-relic, you do not understand the simple advertising ploy Holley used
in the later years, (not in the 70s and mid 80s), The Holley numbers were accurate:
950 cfm and 1000 cfm IF YOU USED THE TEST PRESSURE OF 28" OF WATER TEST PRESSURE. A reminder, for 50 years Holley used 20.4" of water as the standard test pressure. But my buddy Smokey said in magazine articles that 28" of water test pressure "air flow" matched well with the HP of the engines on the dyno.

Do the math and you will see the 750/780/850 carbs rated at 20.4" of water now will show 950 & 1000 cfm at the higher water test pressure 28".

So they did not lie, they just used Smoky's printed words to inflate the carb cfm numbers.

So you only know parts of the story, GTO-relic.

If Barry Grant stayed with the 20.4 test pressure number and he improved the flow of the carb, then he would be doing the job right vs playing games with advertising.

So do some more research on the subject vs posting info that was only 1/2 correct.

Tom V.

"Engineers do stuff for reasons" Tom Vaught

Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.