73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Performance => Topic started by: 78 BIG TEN on February 21, 2008, 08:08:20 pm

Title: Which carb?
Post by: 78 BIG TEN on February 21, 2008, 08:08:20 pm
Stock 350..
Installed Edelbrock Performer RPM.
Leave stock 4-barrel carb or
Holley 700 cfm double-feed?
Title: Re: Which carb?
Post by: JJSZABO on February 21, 2008, 08:17:51 pm
I would keep it stock - from what i read on here, 700 CFM is too much for a stock 350.  Someone else should pipe in though......
Title: Re: Which carb?
Post by: 78 BIG TEN on February 21, 2008, 08:22:33 pm
On the Jeg's site it says the recommended cfm is 650-800.
Title: Re: Which carb?
Post by: 86 chevy silverado on February 21, 2008, 08:39:12 pm
Not for a stock 350. Heres a quick formula to calculate needed cfm;
Engine size x max RPM divided by 3456 = CFM
ex. 350ci x 5200 RPM divided by 3456 = 526.620cfm, a 600cfm carb is enough for your motor.

Title: Re: Which carb?
Post by: choptop on February 21, 2008, 08:57:38 pm
If the stock carb is in good shape, use it. If it is not, I would use anEdelbrock 600 cfm. I have had good luck with these carbs, but make sure you order the banjo fittling so the fuel line will clear the stcok aircleaner.
Title: Re: Which carb?
Post by: eventhorizon66 on February 21, 2008, 09:10:59 pm
I would say the RPM manifold is not a very good match for a stock 350.  A performer would be better unless you know you're going to throw some serious parts at it some day.  I agree with the others here, something in the 600 cfm range would be best for a stock 350.  I'm currently using an Edelbrock 600 cfm carb on my Goodwrench 350.  Runs strong.
Title: Re: Which carb?
Post by: Captkaos on February 22, 2008, 11:34:26 am
Ditto on the above, for a stock 350 that sees no more than about 5500 rpm MAX 600cfm is Plenty.  If you did put a 700cfm on it, you will have to jet it down to make it run well.  I agree on the intake as well, you want something that has a power range from about 1500-5500 for a stock 350.
Title: Re: Which carb?
Post by: 78 BIG TEN on February 22, 2008, 11:38:54 am
Well the stock is electric and the 700 is manual. The intake only allows manual choke. Don't really care about gas mileage.
Title: Re: Which carb?
Post by: eventhorizon66 on February 22, 2008, 12:07:51 pm
What do you mean the intake only allows a manual choke?  It doesn't have provisions for a hot air choke (if that's what you thinking), but you can use electric if you want.  And it's not only gas mileage you will lose with too large a carb.  It's vacuum, throttle response, and overall power.
Title: Re: Which carb?
Post by: 78 BIG TEN on February 22, 2008, 12:23:40 pm
On the stock intake the electric choke was screwed on the intake itself. First, can't get the old screw out. Second. I would have to drill a new hole in the Performer intake. I already have the 700 Holley too. Bought the intake and the Holley for $120.
Title: Re: Which carb?
Post by: eventhorizon66 on February 22, 2008, 12:48:25 pm
OK, I think what you are describing is a divorced choke, meaning the choke is operated remotely from the manifold and connected to the carb with a rod.  But on a holley, edelbrock, or later Q-jet carb the choke is mounted directly to the carb (no need to bolt anything to the manifold).  Here's a pic (http://i208.photobucket.com/albums/bb247/1985C10/choke01.jpg) of my edelbrock carb mounted.

You can definitely make the 700 cfm holley run on that engine, it just wouldn't be the best choice.
Title: Re: Which carb?
Post by: 78 BIG TEN on February 22, 2008, 12:55:34 pm
Yes that is exactly what I am talking about. And what do you mean I can make it work? Different jets?
Title: Re: Which carb?
Post by: eventhorizon66 on February 22, 2008, 12:58:34 pm
And what do you mean I can make it work? Different jets?

Yes, you need to dail it in for your application.
Title: Re: Which carb?
Post by: 78 BIG TEN on February 22, 2008, 01:06:22 pm
How hard is it to replace the jets?
Title: Re: Which carb?
Post by: Redneckchevy on February 22, 2008, 01:10:12 pm
On a holly its all about taking of the float bowls and Taking out the old and putting in the new ones...Holley.com has lil videos on hot to do it and stuff...
Title: Re: Which carb?
Post by: 78 BIG TEN on February 22, 2008, 01:40:59 pm
Well which ones will I need?
Title: Re: Which carb?
Post by: 78 BIG TEN on February 22, 2008, 09:05:23 pm
Well there goes that idea. I put the Holley on and it snapped around the mounting holes. So, I have to wait til payday for a new carb. I plan on doing headers and cam. Should I go with a 650 Edelbrock?
Title: Re: Which carb?
Post by: VileZambonie on February 23, 2008, 09:41:57 am
Did you overtighten it? When you install a carburetor make sure you snug it down evenly in an X pattern. The bolts shouldn't go any tighter than 132 in lbs
Title: Re: Which carb?
Post by: Redneckchevy on February 23, 2008, 10:31:50 am
My Holley 4160 called for no more then 80inch pounds...Not to correct vile other Holley's have different inch pounds...But Holley sells replacement parts...So don't give up on that Holley...If u do sell it on ebay...Pepole will still buy it