Edlebrock Carb Exchange Need Advice

[RomanRegal]

Hi, I have recently installed a new 600 cfm edlebrock carb on my 1987 5.7L Mercruiser. I was wondering from those of you who have made the same instalation, of the carb, whether you used an open squarebore to spreadboare spacer or a ported spacer.<br />Thanks Roman

 

[Boomyal]

Re: Edlebrock Carb Exchange Need Advice

Good question Roman. I am converting from a two barrel Holley to a 4 bbl. I just assumed that I would find a ported spacer, just like the two barrel used. I will be installing on an Edelbrock 2120 Performance manifold, which has a longitudinal bulkhead, seperating the right and left banks.<br /><br />Maybe someone here has a definitive opinion? <br /><br />It appears that you have already installed. Which one did you use and why are you asking?

 

[sculbert]

Re: Edlebrock Carb Exchange Need Advice

You will get a little better idle if you use a proted plate. It keeps the airflow normallized at lower rpms. For wide open throttle it won't matter. If yo have asplit plane intake you should make sure you have a plate and gasket that is matched to ensure your sepration. <br /><br />Some people like to use taller riser plates to keep the carberator cooler also. Help get a little better top end.

 

[Northern Eclipse]

Re: Edlebrock Carb Exchange Need Advice

Roman If you have a spreadbore manifold, then you need Edelbrocks adapter plate part# 2732, its only 1/16 inch thick and retail's for about 10 bucks and comes with one gasket, I installed it on my 1994 350 mag with EP performer 2104 intake and 600 EP carb, idles smooth and throttle response is excellent.

 

[RomanRegal]

Re: Edlebrock Carb Exchange Need Advice

I called the people at Edlebrock and the recommended a ported spacer. This will eliminate any lean and rich conditions that may occur because of puddling of fuel in the manifold which may occur with the open spacer. <br />The place where I purchased the 4bbl Edlebraock and the spacer told me that the spacer is so small, less than an inch, that it would not make a difference. I am going to go with ported spacer.<br />Roman

 

[Boomyal]

Re: Edlebrock Carb Exchange Need Advice

Good info from Edlebrock. I found this statement on the Moroso Website. <br /><br />"As a general rule, open designs increase plenum volume for improved high rpm power, while 4-hole designs increase mixture velocity for improved low-speed and mid-range torque" <br /><br />Low to midrange is what you want for a boat. Did Edelbrock say anything about spacer height?

 

[RomanRegal]

Re: Edlebrock Carb Exchange Need Advice

They have a ported spacer they sell. It is about one inch thick. It will add that hight to our installation. I had to make a small modification to my engine hatch. But it was nothing major.<br />Roman

 

[RomanRegal]

Re: Edlebrock Carb Exchange Need Advice

Just for your info. We finished the changeover this afternoon. Dropped the quadrajet and fitted the Edlebrock. Runs like a charm. I am hoping to avoid flooding, hard starting when warm, and other malfunctions - all the courtesy of a new or rebuilt quad.<br />Roman

 

[flashback]

Re: Edlebrock Carb Exchange Need Advice

Ive had an AFB which i understand is an edlebrock, on a 350 merc, along with a ported spacer about a half inch thick, and an aluminum manifold (don't know where it came from) china for all i know. anyway, the setup runs real good, I have very good hole shot, top end about 4300-4400 rpm, boat speed about 50 mph and idles very well. although after trolling for 2 or 3 hours, the engine will miss a little when I first slam down the throttle, but it clears up in just a few seconds....I think my carb is 625cfm or maybe 650, but no matter, 600 should do just as well if not better...