Recent content by 4bblfreak

Nick's Garage from Canada, put a 1050cfm Holley list 4604 three-barrel carb w/vacuum secondaries/discharge nozzles on a 427 Chevy, and dynoed it.

here is a model 3916 Holley, 950cfm, 3-barrel carb, with 4 booster venturis, compared to 4064 Holley, 1050cfm, 3-barrel with 2 boosters on primary, and 2 discharge tubes on secondary- comparison they just removed the booster venturis from secondary side altogether, less obstruction, more flow...

I picked up a #6090 for $75 stripped. all it had was 3 castings, and primary jets- nothing else. I'm going to build it using others for parts.

yes, the 950 3-barrel had booster venturis. I just picked one up for $65 the 1050 3-barrel had secondary discharge tubes, without booster venturis. that's how they picked up an additional 100cfm, making it a 1050 cfm. the trap door carbs were a 1960's Holley racing carb and short lived fad...

Bewy- IMHO, with diligent custom work to jetting, metering rods, idle/high speed air bleeds, the 72-up TQ carbs should be able to come close or equal the early CS carbs. The Mopar BB dyno test proved that. It was a list #6922 ? TQ carb if memory serves. It's not difficult to drill/tap for...

on the subjects of discharge tubes vs. booster venturis/nozzles, the old Holley 4604 racing carburetor, 1050cfm, was a 3-barrel with secondary discharge tubes. they were used in racing, including NASCAR. 1969 70 #4604 HOLLEY 3BBL CARBURETOR 1050 CFM DATED 982 Edelbrock Mark ll | eBay

what's this all mean ? bottom line- if you have a 72-up carb, it's a lean carb right from the factory. 75-up was even worse. be prepared to mill, fill, and drill.

this guy hit the nail. truth is, what he did with the air bleeds/idle feed restriction was illegal for car manufactures to do from 1972-onward, the cars could not be sold legally in USA. however, prior to 1972, this is how all the carbs were set up as the industry standard. that's just how...

I'd suggest taking one of the CS carbs out of your collection, measuring everything, and comparing it to the 72-up carbs. Epiphany still strike. There's a good reason those later carbs are $50-$100 each on Ebay.

agreed. that means tightening up the secondaries spring, and richening it up, and removing all the emissions controls- usually. you may take the bog out of it, but with the stock jetting, air bleeds, it's still lean a/f ratio. all the carbs were set up and designed lean for each specific...

that's not the original 1969-71 CS carb if advertised that late, they stopped making those in the 1970s. they made AFB/AVS copies and also called those CS throughout the years. the 9800 series was called a CS around 1980-onward. or it was new old stock NOS early CS carbs that were sitting on...

Bewy, if you sent your carb to a pro carb builder, believe me, he'd be changing the air bleeds. that's why modern Holley, QF, etc. carbs, all have tunable air bleeds, threaded in. it's become the standard of the industry. tunable threaded emulsion bleeds in the metering blocks on a Holley...

Bewy, the 72-up TQ carbs use the Aerosol design on the secondaries until 1984. if you're using that carb, you're already using that design. millions of Chrysler cars used it during that time period, and any surviving running 4 bbl. cars from that era, are still using it, on the secondaries...

ok thanks for that info.

ThermoQuad tuning at Cruise