well bear all i've read from you are other peoples opinions and stuff youve heard-where's your 10 sec car since your such an obvious expert engine builder/tuner

 

Well, back when I was racing my own cars (60's and W's), there were no 10 sec street cars. Lots of 12 second cars and I owned one and won lots of local races with it and even a championship or two. Since then I start boat racing, being my own crew chief, wrench and driver. In 13 years I won 11 Regional, 7 Divisionals Championships, 2 Seconds in the Nation high point championship, 2 National High Point Championships and 3 records. I also worked a paid mechanic on several other boats during the period. Is that enough or are you still think I don't know what I'm talking about. Oh yeah, I was a certified professional mechanic during this time also, but like you say"what the hell do I know!"

 

i have a college degree in high performance engines,won many races and had a handful of 10-11 sec cars built and tuned by me-don't claim to know everything! btw anyone other than bronco521 have any helpful advise they would like to add?

 

I always liked competing against the guys with college degrees. All that book learning' taught them nothing about how the world really works. Usually take about ten years for them to ketch up to the rest of the racer.

One last question, if you're fricken learned and smart about cars and engines, why are you on here asking others what you should run for a carb? Somehow your claimed extensive high performance history doesn't match your newbee question.

 

well this was fun.

 

yeah one can usually be a certified engine builder by reading a book,no hands on what so ever-i'm done arguing with bear the dumb old redneck since he knows more than everyone on here and won't share any of his perfection

 

Again, If what you say is true about yourself, why the hell are you asking anyone here about carbs sizes, since if what you claim is true you would already know what carb would be best. The answer would seem very apparent to any logical person.

 

once again i'm asking if anyone has a similar combo and what they are using?opinions are useless,every motors different bbc,bbf just cause they're the same size doesn't mean they require the same carb,formula figured-most of the motors i have built and tuned were sbf's,background or not mr.boat racer-boats to cars sounds like apples and oranges

 

You know less than any normal 16 year old knows about motors. And your statement about a engine in a car and and engine in a boat being different proves it.

 

It seems like everyone is a little right and a little wrong, I dont know which, but i would say with that cam grind and an automatic and not knowing the volumetric efficiency of the motor without a dyno run that a 750 vacuum secondary is the way to go......i just spoke with my engine building brother who says the 600 would probably not give it the air its needs with that cam setup and the double pumper would be too much with the auto but who really knows

 

I have a fairly well built 460 and 600 Edelbrock cfm does just fine. I have trickflow heads, a roller cam, trickflow roller rockers, L&L headers, and 10:1 compression. It is a street engine in a 78 ford f-250 4x4 that I use to pull my boat on the weekends. It has good power, and good throttle response. I used to have a 700 cfm Edelbrock on it and eventually it gave me troubles. I wanted to replace it with the same, but the parts guy at NAPA said it would probably be fine with a 600 Edelbrock and he didn't have a 700 in stock. I seriously doubted it work well. But, as it turns out, he was right...it is just fine.

 

i also run a 600 on my 460 powered highboy, and it runs great, but it weighs over 6000 lbs, he mentioned a 3800 lb vehicle, and from what i understand a lighter vehicle can benefit from a larger carb, the heavy ones need the smaller carb for picking up wind speed to get things moving........once, back in the day i put a 650 double pumper on my truck ( it was off of my 289 powered 67 mustang which ran like a raped ape) and it fell flat on its face with anything other than light throttle, i know that cubic inches are not the only determining factor for this puzzle because i also at one time tried a 600 holley vac secondary on the mustang and it lost all of its raped apeness and it gained nothing at any rpm range

"my novice experiences"

 

i have a 400 in the truck now-rv cam,performer intake,600dp carb,otherwise stock-good throttle response,jetted way up,just runs lean,i put a 750 on it seemed a little rich,650 would probably be just right-btw thanks for the reply's

 

keep us updated

 

Great post! Not! I would shoot for the 650 on a street engine, it will make better signal response at lower RPM's and allow for better metering down low. It will still work fine up to 5 grand or so....anything more than 5 grand and the OEM valve train is not to happy any ways. I run a 460/521 with a 1450 Pro-Systems dominator......but hey what does Patrick at Pro-Systems know?

Really, over carb'ed engines are common. Many folks want to buy a 850 or 750 for a small block chevy as well....they think is a 650 is good......an 850 must be better! The truth is that you need to have a venturi size that flows enough air to properly meter off idle. If you over carb, you loose the lower RPM responsiveness. Once the RPM's pick up, you will get to the point that the carb is getting enough signal response to meter, but it is normally preceeded by a nasty bog or flat spot as the 4 barrels open and the power valves dump way to much fuel in on the airflow. Unless your racing, a slightly smaller carb will normally meter better and have better seat of the pants feel to it. You dont want to over carb by much, but at the same time you dont want to under carb it by a large margain. You have gotten enough information in this muddy post to ball park in on the correct answer, now you make a decision and go with it. Chances are a 650 or 750 will work fine for you, the 650 being the better bet unless you feel that you will be doing higher RPM runs often. If this is street driven with an occasional high RPM run...stick with the smaller of the choices. If you run the dog-snot out of it ever day and you know it.....go a bit bigger because your most likely going to like the abilty to let it breath up high a bit better. As you stated, you have ported the heads, stealth intake, and headers on a street cam....the 750 may be the better choice! I know I am not directly giving you a reply to what carb to use.....but a 4150/4160 750 vac secondary with a good tune on it may be the way to go!

My 521 with the big carb runs 8600 RPM and makes 950+ HP at the crank, so you have to know when to leave the formula alone and go with your track experiance. Your build is a very typical warmed up street engine, and there are plenty of guys out there with 750 carbs on similar engines. Much of it has to do with the tune on the carb also.....If you open a box and bolt on a carb it may be close...or may be in another galaxy as far as tune goes. Holley carbs are easy to tune, and you can spend a weekend nailing it in pretty close by tuning and changing a plug and tuning and changing a plug......Thats what I do until I get it right on the money...or as close as I care to get.