Help with Carb selection for Pro-Touring 455 Olds big block

[real57vetteguy]

Hi guys,

I will go ahead and let you know that this is my first Carburated engine, I have always run fuel injection. With that being said I am a little out of my relm. Any way this might open up a can of worms but I have a 455 big block, bored .30, Edelbrock heads with minor port work, performer intake with minor port work, 242/572 custom grind cam, headers, magnaflow exhaust, 10:1 compression.
I am looking to purchase a new carb, the car currently has been driven 31 miles with a 750 quadrajet and its really losing power above 2800 RPM. Timing is correct, plenty of fuel pressure. line size is fine, plenty of vacuum, etc etc.
I am debating a Ultra Street Avenger 770 V.S. carb or a Quick Fuel SS 780 V.S. I am also running an Art Carr 200R4 with a 3:23 posi rear. The car weighs 3500 lb with driver and fluids. What would you suggest?



Thanks

[cmraman]

I have a Holley 750 on my Olds motor. If you plan on doing events with it, then step up to road race floats.

[carguykeith]

I would think an 850 with annular boosters would be more appropriate if your turning it over 5,500. If you have the extra $, I would recommend a carb builder instead of an "out of the box" or at least a wideband to help tune it.

[AintQik]

Pro Systems was the same price as a good out of the box Holley. Tell them what ya got, and what you do and Patrick will have a carb built for ya.

[real57vetteguy]

I would think an 850 with annular boosters would be more appropriate if your turning it over 5,500. If you have the extra $, I would recommend a carb builder instead of an "out of the box" or at least a wideband to help tune it.

Those big block Olds engines arent to RPM friendly, 5500 would be the MAX

[Chevelle598bb]

I would think an 850 with annular boosters would be more appropriate if your turning it over 5,500. If you have the extra $, I would recommend a carb builder instead of an "out of the box" or at least a wideband to help tune it.

Those big block Olds engines arent to RPM friendly, 5500 would be the MAX

Nope the olds motors are not known for turning high rpms. But the 850 annular discharge would work great on that motor. The annular discharge booster creates a better fuel atomization out of the booster than the standard down or dog leg booster. The annular will make more power throughout the entire rpm band than the other style booster. The annular discharge booster is also easier to tune and has better driveabilty. The only issue is you cant get an annual discharge booster in a vaccine secondary carb or at least not that I know of.

[carguykeith]

Those big block Olds engines arent to RPM friendly, 5500 would be the MAX

That all depends on the big block Olds... Note my signature.

I still say an 850 with annulars is the way to go, double pumper might take a little more time/ effort to get right but will almost always out pull vacuum secondaries. If I had the $ I would send my carb out to a builder though, someone above emntioned a good one but there are lots out there. Heck we have what I consider to be an awesome carb builder right here on the forum, Shaker455 what do you think?

[sam 74]

my best guess from the info you posted would be an 800 or 830 cfm, holley would my preference. i doubt you'll need anymore than that.

[real57vetteguy]

That all depends on the big block Olds... Note my signature.

I still say an 850 with annulars is the way to go, double pumper might take a little more time/ effort to get right but will almost always out pull vacuum secondaries. If I had the $ I would send my carb out to a builder though, someone above emntioned a good one but there are lots out there. Heck we have what I consider to be an awesome carb builder right here on the forum, Shaker455 what do you think?

Keith,
I GREATLY appreciate the help. Just keep in mind this car will never see the drag strip, its life will be mostly the power tour, lots of stop and go traffic cruise ins etc, I do want power, but I mainly want drivability. Most of the cars I have been in with a double pumper ran awesome but loaded up in traffic, but let me say this I AM A CARB IDIOT. thats why i am here asking for advice, and your advice is very important to me!

[real57vetteguy]

I think I am just going to bite the bullet and call up Patrick James of Prosystems. Has anyone used him before?

[AintQik]

Got my carb from Patrick on Friday.

[Fuelie Nova]

If its anything like the one he did for me you'll be happy!
Tom

[Shaker455]

Hi guys,

I will go ahead and let you know that this is my first Carburated engine, I have always run fuel injection. With that being said I am a little out of my relm. Any way this might open up a can of worms but I have a 455 big block, bored .30, Edelbrock heads with minor port work, performer intake with minor port work, 242/572 custom grind cam, headers, magnaflow exhaust, 10:1 compression.
I am looking to purchase a new carb, the car currently has been driven 31 miles with a 750 quadrajet and its really losing power above 2800 RPM. Timing is correct, plenty of fuel pressure. line size is fine, plenty of vacuum, etc etc.
I am debating a Ultra Street Avenger 770 V.S. carb or a Quick Fuel SS 780 V.S. I am also running an Art Carr 200R4 with a 3:23 posi rear. The car weighs 3500 lb with driver and fluids. What would you suggest?

Thanks

I'm not clear on your cam specs but an off the shelf choke towered annular 850 would work fine on your combo and still have some nice bang when you want it.
Jeff