Anyone have any recommendations on a good RR or Auto-x carb? Looking for something that I can put on right out of the box (no modding floats, etc) 650-700 CFM range

 

This "out of the box" carb thing is insane (not a particular jab at you, but many people seem to think that you can buy a carb that runs great "out of the box"). Do you also plan on not changing jets to match the fuel curve your engine demands?

That said, most of the guys I've autocrossed with have run Holleys with good success.

 

IMCO you really ought to consider having someone such as Pro Systems custom tailor one (and at their recommended CFM rating) for your specific needs. My $.02

 

No offense taken, I used to be one of those many people. But I just got an LM2 so I do plan on getting the fuel curve correct, but I am not looking to piece together a carb. If I was keeping the sbc forever I would absolutely get a carb built to my specs, but Im really not looking to spend that kind of $$ when LSx power is in my future.
Just looking for something that wont starve under hard braking and cornering like my holley 650 does now

 

I'm confused about the starving part. There's very little fuel required during hard braking, and only modest fuel required during cornering. What happening that it sounds like the system is starving?

 

Under hard braking, the car will stall. Carbs are way out of my knowledge area so Im not sure if it is stalling from lack of fuel, or maybe flooding itself?

 

If the float level is too low, you can starve it.

If it's too high, you can flood it.

No matter what you do, you'll need to make sure your floats are operating well and set correctly.

 

I would fix your 650. Is it a double pumper? If it is buy bigger end bowls with the glass sight glasses so you can easily see the fuel level. Buy the larger diameter stainless or titanium needle and seats. buy new rubber squirter diaphragms

 

Holley HP Ultra.....bolt it on and go! Add some float vent extensions your probably done otherwise BLP in Florida Mike Laws is excellent at what he does. His father learned how to tune Holleys by drag racing a 435HP Vette......

 

It is and I would, but I want something without a choke horn. Carburetors are a foreign language to me. I am just looking for something to drop on and go and do some minor tweaking with an air/fuel meter.

The HP Ultra looks sweet, but $700? I thought racing was a cheap sport?

 

A machinist should be able to mill your choke horn off for a few bucks. Why do you want it off?

 

I have a friend, he is a smart dude like Smokey Yunick level smarts. He is now building what will probably be the fastest Australian Pro Stock motor (400 cu/in 1100+HP) my friend Bob knows carbs from Holleys/Webers to Kehins used on road racing motorcycles. When I was doing my no limit SBC build and the subject of carbs came up Bobs response.....HP Ultra 750 we will probably not even have to rejet it....bolt it on and GO! This guy has done more metering block reworking and reconfiguring than most guys, he had a 390CFM NASCAR Holley he had reworked and was offered $10K for it...he wouldn't sell it! If Bob says 750HP Ultra I'm not one to argue with him, I have some reworked Holleys hanging around my garage if you want a #4779 DP 750 cfm with a choke horn off it, I can sell one for around $175. The old Holleys are OK but not as good as current stuff.... speed costs money how fast do you want to go? I'm a pretty good tuner, my 355 cu/in LT-1 went 12.28@117MPH in autocross trim with a factory hi-rise and "undersized" 650 DP Holley I reworked myself doing 4 corner idle circuits, choke horn removal and main body smoothing. That Holley was DYNAMITE on bottom end and transition off idle, many would say too small but later testing using a reworked 750 showed a loss in 60ft times with a 1.5 MPH increase in trap speeds, the 650 would ET 2-3 tenths better than the big carb, went back to my first effort still in possession of that carb not for sale. Some carbs work better than others Bob says HP Ultras are consistently excellent, this guy knows how to improve a $8000 set of Bob Book Pro Stock Holley 4500 Dominators, I'll take his advice as gospel.

 

Just put a Prosystems on my big block this weekend. Best money I ever spent. Set up for street/roadrace. Perfect out of the box minus a slight idle adjustment. Runs like a Muslim running from a missile! $708.00 to my door

 

Got an AED 850 HO delievered for under $600
Custom tailored

Bet your gas is coming up through the vent tube under hard braking and drowning the motor. Connect the two tubes with a piece of hose and make a hole in the center. Kind of an arch so to speak. Just a thought

Mine did that, lowering the rear float a tad took care of it.
Course that wasnt under as hard braking conditions as you

 

Rear float level to high will flood the car in braking and make it die. The hose trick on the bowl vents work well too. A short extension on the front jets can help with starving on hard braking too. You can also run the front float level a little higher than the rear. These simple fixes will probably cure your problems. If the carb is sized well to your engine, a new carb is probably not going to gain you much if anything. Just fix it!