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View Full Version : Carb and intake for cowl hood


1st_chevelle
08-28-2012, 01:41 PM
Well there comes a time in one's life when he needs a new carb and intake. That time is now. Or even sooner if I can find some tnt and send that damn rochester carb to the moon. I got a 468BB stuck with one of those and it's killing my performance. It feels like it's barely making 150HP when I know it's capable of at least 400HP and more. Anybody have a good combo that works with a cowl hood or at least point me in the right direction? Thanks for your time and consideration.

shadowgray396
08-29-2012, 08:07 PM
Not knowing more details on the motor you probably will need at least a 700 to 750 cfm carb. It depends how your motor is built. I'm no expert in this area so I hope someone else will chim in for you. What cam are you running, compression, etc?

1st_chevelle
08-30-2012, 10:15 AM
I'll have to get a hold of the motor guy but it's a stock reground cam and compression is 10:1. A really great shot (Greer Performance) recommended that a 750 should suit it just fine. Don't need a double pumper or anything just a 750 and intake manifold that works with it.

carpoor
08-30-2012, 01:42 PM
A 750 tuned right will suit the needs of 98% of all applications. Many of my friends with big inch LS-based engines run a 750. A few have tried bigger carbs - with lackluster results. One of the slower cars runs mid 10's on drag radials, through the mufflers.

I would think an Edelbrock performer RPM, Weiand Stealth, or something of the like will feed your engine plenty of air.

Hank70SS
08-30-2012, 04:31 PM
Agree, a 750 or 770 (Holley's new carbs are 770's) would be good unless it's a very high reving 468 and used for mostly racing. Check the Holley and Edlebrock websites. They'll tell you what size carb based on the basics of the engine and how it's used, street, street/strip or strip only.

jpekarek
08-31-2012, 01:43 PM
Or even sooner if I can find some tnt and send that damn rochester carb to the moon.

Hate to say it, but I would find someone to rebuild that Q-Jet properly. It's already an 800cfm. When they are set up correctly, they will run with any Holley or Edelbrock out there. I know a lot of people are going to scream and yell about how crappy they are and how great Holley's are, but if they really were crappy, they wouldn't have used them on a billion cars, even ones making 400-450 horsepower. I have had many performance cars running way over 400 horsepower using a Rochester. They run smooth and make great power, just as much as any Holley, when set up right. Problem is that most people dont understand how they work so they call them junk. Which is the furthest thing from the truth. The other carbs are all good, Holleys and Eddys are great, even a little easier to tune for most people. But remember this, NOTHING runs perfectly right out of the box, no matter what they say. The floats are almost NEVER preset from the factory. If you don't set the floats then it will never run the way it is supposed to.

carpoor
08-31-2012, 02:27 PM
I am having Cliff Ruggles redo my factory Quadrajet. I prefer them to the other stuff out there, but to each is own.

jpekarek
08-31-2012, 03:22 PM
I have 2 Holleys, 2 Edelbrocks and a Quadrajet running on 5 different cars. They all run great. The Q-jet car can whip the crap out of 3 of the others.

shadowgray396
09-01-2012, 10:45 AM
My Q jet runs great for me once I got it rejetted

Ms Grumpy
09-01-2012, 01:02 PM
I know I have a Holly 750 hanging around, that was what I had prior to the EFI. I really liked it. I think it is all personal preference, and a lot of research to find what will work best. And if your mechanic is someone you trust, then follow his advice.

But I will tell you, the guys on here have had "Driving" experience with the different carbs, and sometimes that means more to me than what a mechanic thinks.

1st_chevelle
01-05-2013, 11:34 PM
Man I am so sorry for not replying to this thread with everyone's advice and for now digging up a 5 month old dead thread. What I am truly worried about is fitment issues with the cowl hood. I paid extra for this and I'm keeping the hood. Do most combos fit without issue or am I worried about nothing? I've been searching for the last few months and I've been saving when I haven't been buying my pistols. In an unrelated note the guy who built it (and it's my fault for not checking) decided not to grease any of the new bushings and now they're all shot. I've got a busy an expensive summer.

Hank70SS
01-06-2013, 07:08 AM
A high rise intake and really any 4 barrel carb will fit under a cowl hood. Now if you're trying to fit a stock cowl induction air cleaner on top of it that may be a problem. I have a 454, high rise aluminum intake, GM version of the Edlebrock RPM Performer and Holley 770 carb. On top of that sits a 4" high 14" diameter open side air cleaner.

1st_chevelle
01-06-2013, 05:11 PM
I could care less about the stock air cleaner at this point. Hank thank you that is the best answer and the best info I could have hoped for. Where did you get your parts?

Hank70SS
01-07-2013, 07:21 AM
Engine is a GMP 454HO crate engine. It comes with aluminum high rise intake. Carb is Holley Street Avenger, my son got it with his discount when he was working at an auto parts store. I know, no help to you. Summit or Jegs have good prices, they're both usually the same price for the same part. I would start there.

jpekarek
01-07-2013, 09:50 AM
Same here. '70 Chevelle with cowl hood. 541 BBC and 1000 cfm Dominator with big old air cleaner. Lots of room!

1st_chevelle
01-09-2013, 06:06 PM
The one thing I'm torn about is Holley vs Edelbrock. I like Edelbrock's intakes and Holley's carbs. It's such a hard decision.

jpekarek
01-09-2013, 07:23 PM
Use the one you know best. They can both be tuned to provide great performance. Holleys are very tunable and streetable. Eddys are also very tunable but many people don't know how to tune them right. They say they will run right out of the box, but this is just a starting place. ALWAYS adjust your floats before running the new carb, they are never right on any carb.

Hank70SS
01-09-2013, 07:43 PM
No problem running an Edelbrock intake and Holley carb. In fact that's pretty common. As jperkarek said, go with the carb you're most comfortable with. It will need tuning, so the one you know is the one to go with. They're both good.

1st_chevelle
01-09-2013, 09:29 PM
Thank you gentlemen. I've been leaning toward Holley but I still know JACK about carbs. No idea how to tune or really use them to be honest. I've had my car since July and I've spent a majority of that time in Germany. Now i'm in Kansas waiting April so I can drive back to Indiana and trailer it to the new place in Kansas. I've spent so limited time with it I barely know how it is. I want to do the carb and intake myself which is easy enough but tuning is a whole new ball game.

1st_chevelle
01-09-2013, 09:54 PM
Alright got it nailed down to a Holley 770 Street Avenger and an Edelbrock RPM Air-Gap. I already have a mild cam installed. I want it more for breathing room so I don't have to re buy parts. Thoughts?

Hank70SS
01-10-2013, 06:57 AM
Sounds like a good combo to me.