Corona Carbs

Ishiftem

Well Known Member
Supporting Member 2
So I’m getting rid of my edelcrap 750s and redoing a pair of ‘69/‘70 vintage Carter afb race carbs. I figure I won’t be working much since Illinois is on lock down so now is a good time to play with these things. Got the pressed in plugs out and cleaned up the bodies. Next is airflow improvements. I will be flowing them to quantify how much improvement I made.
 

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427John

Well Known Member
So what s the issue with the edelbrocks are they poor castings or is it shoddy workmanship?Is it a performance deal or leaking,isn't the edelbrock just a newer version of the afb?I've heard lots of guys trash them but never picked up a specific reason why,I mean where theres smoke theres usually fire but I'm just trying to find out what to be on the lookout for I haven't had any issues with the one I'm running yet. -
 

Ishiftem

Well Known Member
Supporting Member 2
So what s the issue with the edelbrocks are they poor castings or is it shoddy workmanship?Is it a performance deal or leaking,isn't the edelbrock just a newer version of the afb?I've heard lots of guys trash them but never picked up a specific reason why,I mean where theres smoke theres usually fire but I'm just trying to find out what to be on the lookout for I haven't had any issues with the one I'm running yet. -
The changes started when federal mogul bought them and still sold them under the carter name. The primary boosters are totally different resulting in a wavering signal to the boosters. Emulsion tubes are different. Air bleed sizes are different. Squirter is different. This pertains mostly to 750s but there are differences in others also. Plus there are manufacturing issues such as having different emulsion tubes and bleed sizes in some carbs.
 

Fathead Racing

Well Known Member
Supporting Member 7
The changes started when federal mogul bought them and still sold them under the carter name. The primary boosters are totally different resulting in a wavering signal to the boosters. Emulsion tubes are different. Air bleed sizes are different. Squirter is different. This pertains mostly to 750s but there are differences in others also. Plus there are manufacturing issues such as having different emulsion tubes and bleed sizes in some carbs.
I've taken apart the eddy carbs and the Carters. Casting is much cleaner and sharp. The eye says the Carter piece is the better carb. I run Carter 600 cfm competition series AFB style carbs. The Eddy carb can be very good with a little work. It's like cleaning up the heads.
 

Ishiftem

Well Known Member
Supporting Member 2
I have not had a true Carter 600 and the Carter/federal mogul/edelbrock side by side for comparison. I’m pretty sure the Carters were all 625 cfm whether they were a race version or street/strip. If it has SA after the number, they were made by federal mogul. The A designated a design change.
 

427John

Well Known Member
The edelbrock I currently run is a 750 and has given no problems so far,but did require extensive re-calibration from the box.It was slightly lean on cruise when the 454 was stock,after the head and cam upgrade was massively lean on cruise and lean on power, to the point that the lean surge on cruise more like a bucking bronco,after the necessary jet,rod,and spring changes and a slight adjustment to pump shot I'm pretty happy with how it runs now.I had a smaller one on the 305 that was in the truck before and it seemed to be ok on it,after I swapped in the big block I stuck it on,and realized immediately how inadequate it was,seemed like no matter what you did it didn't improve anything,what you said about bleeds and emulsion tubes makes things clearer in hindsight.I think that carb would have been a poor match for a decent 327 or 350,it may have worked for a stock smog era 350.
 

Ishiftem

Well Known Member
Supporting Member 2
The edelbrock I currently run is a 750 and has given no problems so far,but did require extensive re-calibration from the box.It was slightly lean on cruise when the 454 was stock,after the head and cam upgrade was massively lean on cruise and lean on power, to the point that the lean surge on cruise more like a bucking bronco,after the necessary jet,rod,and spring changes and a slight adjustment to pump shot I'm pretty happy with how it runs now.I had a smaller one on the 305 that was in the truck before and it seemed to be ok on it,after I swapped in the big block I stuck it on,and realized immediately how inadequate it was,seemed like no matter what you did it didn't improve anything,what you said about bleeds and emulsion tubes makes things clearWeer in hindsight.I think that carb would have been a poor match for a decent 327 or 350,it may have worked for a stock smog era 350.
The mods your making,are they aimed more at increasing flow or creating a more stable signal at the venturi area?
The 750 is pretty restricted on the secondary side. They come with a .107 jet yet have the emulsion tube swedged down to .073. Not to mention the brass tube in the cluster is only .107. Now add a overly large air bleed and you could probably just about remove the secondary jet and it wouldn't run any different. In my race car I saw a big improvement once I shrunk the air bleed, cut of the bottom of the emulsion tube, and enlarged that brass tube in the cluster. On a mild street car, the difference could be made up by playing with the primaries but, on a race motor, the fuel you would need to flow through the primary side would make the primaries overly rich and the secondaries lean cause an unfavorable fuel distribution. The improvements I'm making are mainly for air flow but by reducing turbulence, the metering will also be more consistent. I did a lot of this air flow work on my edelbrock 750s and saw a noticeable gain. These I'm taking a little further.
 

427John

Well Known Member
I was thinking what you were doing would result in both,but was curious if you felt one or the other was more important or desirable,but I guess that since they're both good things it doesn't matter,take them both and smile.
 

425/409ER

Well Known Member
A sharper glass bead to take off corrosion etc. Then size c 40-60 glass bead at 15-20 psi. That peens the surface and closes it up so it can be wiped and puts a little sheen on the surface.

I should pay you to blast my 409 carbs.
 

Ishiftem

Well Known Member
Supporting Member 2
They are brighter than factory new but at least they are clean and I can wipe them off now.
 
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