First Annular booster Holley carb?

[rgalajda]

Picture

[Ron Gusack]

That looks like a 4575 with the choke. We ran one in 70 or 71 on a C454 dual plane that I'm still running today.

[bigblockmark]

So the 4575 is annular discharge?

6214 was early too but I think it had tall/long non annular booster.

[rgalajda]

Would this statement be true?

"Original Dominators came with these single-discharge-port boosters that are very lazy. If you have one of these carbs, the smart move is to exchange these boosters for an annular-discharge version."

[mike laws]

Yes! Changing to annular boosters was the first mod done to these carburetors for any serious racing, even back in the day...

[bigblockmark]

What was the relationship of introducing the intermediate circuit and the annular discharge with 4500 carbs? Were they at the same time? Is the intermediate circuit redundant for many drag race carbs, except when additional fuel is needed that the other 2 circuits can't satisfy. I have had good performance with 2 circuit 4500's but only have experience on medium size BBC engines.

[mike laws]

[rgalajda]

Another feature of the Autolite four-barrels was that they were the first carburetor to incorporate an annular discharge booster venturi way back in the late 1950s.
Holley paid Ford for the use of this design ( annular boosters ) for many years before eventually buying it from them when Ford discontinued making carburetors and started using fuel injection."

This is probably one of the first ( aftermarket ) Dominator carbs. List 6214. Notice, no annular boosters

[GTO Geoff]

The 'original' Holley book by Holley engineer Mike Urich lists the 4574, 6464 & 6214 as being the original 4500 carbs. The 6214 was an IR carb, 1150 cfm, the other two were 1050.

[Right hand drive]

So when would have the 0-9379 and 0-9380 have came out? Any earlier 4150 aftermarket with annulars than those?

Just stumbled across this on fb marketplace. They’re still out there.

Interesting boosters.