.....but what size are they!
Big block carbs.......?
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Big block carbs.......?
How many CFMs were the carbs that came on big block engines from the factory from 396s (65s) to the last 454s? Thanks. 
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From: Millington Illinois
St. Jude Donor '08-'09
The highest HP factory rated Chevy engine was the 1970 454 LS6 in the chevelles. 11.25 to 1 compression, solid lifter cam. This was pretty much an all out racing engine. 780 vacuum secondary holley.
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Drifting
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The engine in my 70 Coupe was stamped CRR, which is the 70 Chevelle LS6 450 HP / Turbo 400 combo. The car was not safe as the suspension was worn, and the brakes were, well you know. I was lookin' for Vipers. The engine was worth more than the car; if I only knew... 4 to 6 mpg...
Burning Brakes
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The highest HP factory rated Chevy engine was the 1970 454 LS6 in the chevelles. 11.25 to 1 compression, solid lifter cam.
Then there was the 69 ZL1 rated at 600HP. Two produced and VERY expensive. 12:1 compression, aluminum block, aluminum heads, 850CFM Holley... all the go fast stuff Chevy had available.
Ed
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Close. The 66 L72 was also rated at 450HP until approx mid October, 1965. It was then downgraded to 425HP because insurance companies were having cows! Same engine, same car, but marketing decided to apease the insurance companies, so it went to 425HP.
Then there was the 69 ZL1 rated at 600HP. Two produced and VERY expensive. 12:1 compression, aluminum block, aluminum heads, 850CFM Holley... all the go fast stuff Chevy had available.
Ed
Then there was the 69 ZL1 rated at 600HP. Two produced and VERY expensive. 12:1 compression, aluminum block, aluminum heads, 850CFM Holley... all the go fast stuff Chevy had available.
Ed
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Not that the flow ratings mean much or have a direct relationship with performance, but I remember reading somewhere that Holley and Rochester did not use the same method for rating their carbs- so there was a slanted playing field.
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St. Jude Donor '08-'09
Close. The 66 L72 was also rated at 450HP until approx mid October, 1965. It was then downgraded to 425HP because insurance companies were having cows! Same engine, same car, but marketing decided to apease the insurance companies, so it went to 425HP.
Then there was the 69 ZL1 rated at 600HP. Two produced and VERY expensive. 12:1 compression, aluminum block, aluminum heads, 850CFM Holley... all the go fast stuff Chevy had available.
Ed
Then there was the 69 ZL1 rated at 600HP. Two produced and VERY expensive. 12:1 compression, aluminum block, aluminum heads, 850CFM Holley... all the go fast stuff Chevy had available.
Ed
You are right, all those and the LS6 were rated at an RPM much lower than peak HP to keep the insurance co's off their back.
Burning Brakes
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Good point Kevin. As a matter of fact, I just had this conversation with John Hinckley (JohnZ) and although Dobbins states the ZL1 was a "600HP monster", it was still factory rated at 430HP like the L88. In reality, with headers and an open exhaust, both produced more in the neighborhood of 560-580HP. Still much more than Chevy wanted to let on about!
Ed
Ed
.....1200 HP 18 ft. Drag boat
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From: Millington Illinois
St. Jude Donor '08-'09
Good point Kevin. As a matter of fact, I just had this conversation with John Hinckley (JohnZ) and although Dobbins states the ZL1 was a "600HP monster", it was still factory rated at 430HP like the L88. In reality, with headers and an open exhaust, both produced more in the neighborhood of 560-580HP. Still much more than Chevy wanted to let on about!
Ed
Ed
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From: Some days your the dog and some days your the hydrant.
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I recall something about wet and dry flow testing methods. Holley used wet flow and QJ used dry flow. The dry flow would show a higher cfm flow because the medium was less dense when compared to wet flow testing that Holley uses. Anyone else shed some light on this?