When was the holley 4776 released

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54chevkiwi
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When was the holley 4776 released

Post by 54chevkiwi »

Hey so, im wondering when the 4776 was released and used commonly as an option in place of the 660 center squirter in tunnel ram applications...

The guy doing carbs for me has a pair of 660s and also a pair of 600 double pumpers (4776).. he says the 4776 carbs will be more user friendly on the street and still be as good raced as the 660s....

The engine is a 70s style drag engine, camel humps, tr1y tunnel ram, 400 block, 327 crank.... think the two lane blacktop chevy engine but the small block version...
About 550-580hp according to the builders guess..

Cruise rpm might be around 4000 at 70mph i guess? Cam will be solid flat tappet in the neighborhood of 260-268 at .050 and .580 lift, rear gears might be around 5.14, but will decide when the dyno curve is infront of me...,

So..
Being the 660s were designed as a WOT tunnel ram carb, are 660s really as temperamental-even with power valves-as the internet makes out..? Would 600s still be considered a good era correct option that fit in..?
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Re: When was the holley 4776 released

Post by Walter R. Malik »

The Holley L-4776 was probably released sometime in the early to mid 70's.
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Re: When was the holley 4776 released

Post by 54chevkiwi »

Thanks walter, appreciate it. I would run the numbers if i had the carbs with me but for now thats all i need to know.
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Re: When was the holley 4776 released

Post by F-BIRD'88 »

To equal the power of the 660's use 2x750 hp carbs on the tunnel ram.
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Re: When was the holley 4776 released

Post by F-BIRD'88 »

A very street strip tunnel ram friendly carb set that is also period correct is the Carter/Edelbrock AFB carbs.
The larger cfm carbs make the most power.
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Re: When was the holley 4776 released

Post by Joe-71 »

I have a 4776 that I purchased in 1972, so early '70s. Good carb, but too small for most engines making over 300 hp IMO. Joe-71
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Re: When was the holley 4776 released

Post by 54chevkiwi »

Joe-71 wrote: Fri Aug 27, 2021 2:52 pm I have a 4776 that I purchased in 1972, so early '70s. Good carb, but too small for most engines making over 300 hp IMO. Joe-71

So two would be good for 550-580hp in your opinion..?
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Re: When was the holley 4776 released

Post by Mummert »

The 4777 is the same venturi and booster with 750 1-11/16 throttle plates, vs 1-9/16 on the 600's. It needs the bottom of the main body chamfered to clear the bigger throttle plates. But its an easy way to pickup 50 cfm.
Holley intentionally uses thick butterflies on the 4776 to get the cfm down. I made .050" brass throttle blades for my 4776 that I have on a 4.3L offroad car. Flow is jumps quite a bit and low speed manners are much better than the 750 butterflies.
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Re: When was the holley 4776 released

Post by Walter R. Malik »

Mummert wrote: Fri Sep 03, 2021 7:17 pm The 4777 is the same venturi and booster with 750 1-11/16 throttle plates, vs 1-9/16 on the 600's. It needs the bottom of the main body chamfered to clear the bigger throttle plates. But its an easy way to pickup 50 cfm.
Holley intentionally uses thick butterflies on the 4776 to get the cfm down. I made .050" brass throttle blades for my 4776 that I have on a 4.3L offroad car. Flow is jumps quite a bit and low speed manners are much better than the 750 butterflies.
4777 venturi, booster and throttle bore is just like a 660 ... funny how that is.
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Re: When was the holley 4776 released

Post by frnkeore »

A little OT, I suppose but, how much flow might be picked up by using a 1 3/4 throttle plate, on a 3310-1 (1 3/8 x 1 7/16) 780 or a 4779 (1 3/8 x 1 3/8) 750?
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Re: When was the holley 4776 released

Post by VMC »

FWIW, I'm the guy who's building the carbs for Ben.

He and his builder initially suggested 660's, but simply put they just aren't street friendly carbs without mods. Without power valves, they're going to be rich at part throttle cruise. The quickest solution there is a metering block swap. Then there's the progressive linkage which brings the secondaries in a lot sooner than they need to be on the street. Since they don't have a rear metering block, either you have to add one or modify the existing metering plate to accept replaceable bleeds for tuning.

After considering all this, I suggested using a pair of 4776 600 double pumpers instead. First and foremost, 1200 cfm is MORE than enough for his application, never mind 1300+. They already have primary power valves, so that cleans up part throttle operation. They have primary and secondary metering blocks, so that simplifies tuning. They have a standard mechanical secondary linkage which doesn't bring the secondaries into play too early.

I did discuss mounting scenarios with Ben, and while the 660's could be mounted inline, one still has to come off to change either the secondary jetting in the front carb or the primary in the rear. Sideways mounting eliminates that issue, but does require a more sophisticated linkage--but Ben assured me that wouldn't be a problem for him.

Overall the 600's are a win/win/win/win over the 660's in this situation. And the 4776 carbs came out in late `70 or early `71.

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Re: When was the holley 4776 released

Post by F-BIRD'88 »

2x750's will make more power . It will be a bit quicker and faster with these.
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Re: When was the holley 4776 released

Post by 54chevkiwi »

VMC wrote: Sat Sep 04, 2021 12:18 pm FWIW, I'm the guy who's building the carbs for Ben.

He and his builder initially suggested 660's, but simply put they just aren't street friendly carbs without mods. Without power valves, they're going to be rich at part throttle cruise. The quickest solution there is a metering block swap. Then there's the progressive linkage which brings the secondaries in a lot sooner than they need to be on the street. Since they don't have a rear metering block, either you have to add one or modify the existing metering plate to accept replaceable bleeds for tuning.

After considering all this, I suggested using a pair of 4776 600 double pumpers instead. First and foremost, 1200 cfm is MORE than enough for his application, never mind 1300+. They already have primary power valves, so that cleans up part throttle operation. They have primary and secondary metering blocks, so that simplifies tuning. They have a standard mechanical secondary linkage which doesn't bring the secondaries into play too early.

I did discuss mounting scenarios with Ben, and while the 660's could be mounted inline, one still has to come off to change either the secondary jetting in the front carb or the primary in the rear. Sideways mounting eliminates that issue, but does require a more sophisticated linkage--but Ben assured me that wouldn't be a problem for him.

Overall the 600's are a win/win/win/win over the 660's in this situation. And the 4776 carbs came out in late `70 or early `71.

Eric

Thanks eric
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Re: When was the holley 4776 released

Post by 54chevkiwi »

Arrived, courtesy of eric
B0461A79-6220-4B4C-8ED3-7DC77B123014.jpeg
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