800cfm on mild 360 ?

-

Johnny Dart

Well-Known Member
Joined
Nov 30, 2006
Messages
8,716
Reaction score
3,947
Location
So Cal
We know back in the day the trick was to swap an original 340 AVS ( about 600cfm ) for the larger bore version about ( 750cfm ) from the 440 magnum. It was also no secret then that the 340 responded favorably to the increased carb capacity, suggesting that a larger carb would add to the HP bottom line.

Brings me to today. I have tried a 600cfm,650cfm,750cfm Eddies on my mild 360.
The 600cfm ran very well, with great response out of the hole.
The 650cfm Thunder Series has been the best out of the three, with great response, and better top end.
The 750cfm just didn't feel right. But there has been a lot of discussion about the Ede 750cfm, and its design. None favorable.

That brings me to the Ede 800cfm. I bought this carb for a 440 project that went south. I can't remember if I ever has this carb on my 360 car, or not. Not sure how it is going to run, but I guess there is only one way to find out. Stay tuned.

P_20200811_102138_LL.jpg
 
Ok...Lets not get crazy. :eek:
Works great, and without headers.... watch the 1st minute. I run a 750 double pumper on my 360. Even when it had stock exhaust manifolds and stock heads, it ran the best ET at the strip (over a 600 eddy, and a vacuum secondary holley). That was with 2.45 gears and stock converter. My point is the 800 may not run faster than the 650, but it shouldn't give anything up to it either
 
Last edited:
First step...Always check the float level on these Eddys.
More often than not, they are off. This one is spot-on, I must have already checked them. :) I've had this carb on the shelf for a while. Honestly can't even remember when or where I got it. LOL It looks like its never even had gas in it. That and the fact that it doesn't have the Edelbrock Chrysler adapter, I'm going to assume I've never had this on the car.

P_20200811_111732_LL.jpg
 
Hmm, you never know unless you try it! honestly im thinking of going with 600cfm on my slant, the 500cfm if good but i feel that the four speed can use a little more reving up. Maybe ill hook up a vac gauge and see what shes telling me?
 
Tech tip for the Eddys.......ChapStick.
Put a thin layer around the gasket. You will thank me when its time to remove again.

P_20200811_112743_LL.jpg
 
I had picked up a dbl pump Holley at a swap meet, didn't recognize the number.
I brought it home, cleaned it up, checked it over, and found it to be an 830 cfm, never had one of them.
I replaced the 780 on my son's 340 with the 830.
My son came home from work, later took the Dart out, and about 5 mins later, he was back.
I watched him go and open the trunk, then go and open the hood, then he started walking up to the house.
I came out on the porch, he said "I don't see a nitrous bottle, what'd you do."
"Bigger carb"
He gave me a thumbs up, got back in the car, and away he went.
 
800cfm Eddy installed. Straight forward, no issues.
Now the fun part. For starters, get the idle and a/f ratio correct. Test and Tune. To be fare to the carb, this will take awhile. Not sure I will get into jetting, maybe just try some different rods, per the chart. Will get back with the results.

Side note: This car already ran like a raped ape with the 650cfm Thunder Series carb. All smiles every time I drove it.
What's a guy to do. :)

IMG_20200811_124447459.jpg
 
Started the car and let it warm up. Set the idle up to 950rpm to adjust a/f for highest rpm's. After that, set initial idle back to around 750rpm.

Observations:
1. Wacked the throttle a couple times, and she hit hard !
2. There is no shortage of gas. Had to get out of the garage Whew !!!!!! But that's the point of a bigger carb right ?

Next up, get her out on the street, and see what she does. It's Hot here, so I'm done for the day. :)

IMG_20200811_132306102.jpg
 
Started the car and let it warm up. Set the idle up to 950rpm to adjust a/f for highest rpm's. After that, set initial idle back to around 750rpm.

Observations:
1. Wacked the throttle a couple times, and she hit hard !
2. There is no shortage of gas. Had to get out of the garage Whew !!!!!! But that's the point of a bigger carb right ?

Next up, get her out on the street, and see what she does. It's Hot here, so I'm done for the day. :)

View attachment 1715576487
Is this 800 the thunder series?? I've not tried any of the thunder series yet, but I'd like too...
 
Is this 800 the thunder series?? I've not tried any of the thunder series yet, but I'd like too...

It is not, but the 650 is. The way to tell is the black linkages/parts on the Thunder Series. The ease of adjusting the secondary air valve is awesome. Highly recommend the Thunder series.
 
We know back in the day the trick was to swap an original 340 AVS ( about 600cfm ) for the larger bore version about ( 750cfm ) from the 440 magnum. It was also no secret then that the 340 responded favorably to the increased carb capacity, suggesting that a larger carb would add to the HP bottom line.

Brings me to today. I have tried a 600cfm,650cfm,750cfm Eddies on my mild 360.
The 600cfm ran very well, with great response out of the hole.
The 650cfm Thunder Series has been the best out of the three, with great response, and better top end.
The 750cfm just didn't feel right. But there has been a lot of discussion about the Ede 750cfm, and its design. None favorable.

That brings me to the Ede 800cfm. I bought this carb for a 440 project that went south. I can't remember if I ever has this carb on my 360 car, or not. Not sure how it is going to run, but I guess there is only one way to find out. Stay tuned.

View attachment 1715576384

LMAO, same exact boat here.
 
Works great, and without headers.... watch the 1st minute. I run a 750 double pumper on my 360. Even when it had stock exhaust manifolds and stock heads, it ran the best ET at the strip (over a 600 eddy, and a vacuum secondary holley). That was with 2.45 gears and stock converter. My point is the 800 may not run faster than the 650, but it shouldn't give anything up to it either


And some years back on my 10.5-1 - 360.... Twin AFB 600’s.


upload_2020-8-11_17-27-30.jpeg
 
First step...Always check the float level on these Eddys.
More often than not, they are off. This one is spot-on, I must have already checked them.

View attachment 1715576406

Also check the fuel level after you have adjusted the floats to make sure it covers the pump well. I had 2 800 AVS carbs that had to be adjusted much higher to get the fuel high enough. Make sure you do it on a level surface to get a good accurate indication of where it is. I ended up cutting up a top plate from another carb to see where the "Real" float level was when adjusted to different heights

thumbnail

thumbnail
 
Hmm, you never know unless you try it! honestly im thinking of going with 600cfm on my slant, the 500cfm if good but i feel that the four speed can use a little more reving up. Maybe ill hook up a vac gauge and see what shes telling me?
I don't want to hijack thread but I bought a 65 dart gt w/ 225 sl/6 4spd. It had 3:55 rear gears, and dual 3into1 tube headers fed into 2-1/2" true duals. It came with a 750dp Holley, but that was way overkill. I tried a Carter 600, better but not quite right. Tried a Carter 500, and it was just right. At least until the throttle blade set screws fell out.
 
Remember that if the carb is to big it will probably run lean. Not enough air velocity to pull fuel. I run a 800 thunder. I have to run an AVS for the class. Works fine for what I do. The base is the same casting as the AFB so it has the holes in the Venturi for the counterweighted shaft. I sealed those up to clean up the air flow and did some blending in the air horn area.

A77AD84C-5E94-444C-9983-49A2C8C41F54.jpeg


FB2C5ABD-F0A6-4703-B6AA-03A4DD5D6A15.jpeg


712B5447-F3D6-482D-BF2D-F0593993058D.jpeg
 
Update:
So I took the car out this morning with cooler temps out.
Remember in this writing, this is my opinion, and only my opinion. You're experience may differ. I'm not one to say how awesome something is, just to say it, so here we go.

First impression leaving the driveway. The car idled fine, no stutter or anything out of the norm. Getting to my favorite straightaway/test road. Out of the hole the car hit pretty hard, feathering it for traction with the 215 70/14 tires. Mid range was where the problem was.maybe to much gas in the transition ? Just a little sloppy in the mid. Once it got past that in the top end, it ran pretty well. Driving and kickdown. Again there was a flat spot in the middle, and then picked up after kicking it down.

Conclusion at this point:
The best way to get this carb to run at its best would be running it on a dyno and with the help of a wideband a/f ratio gauge, and Ede tunning kit. With today's gas, the old school way of checking the plugs is a crap shoot at best. Plus is verly timely. If I was running this car at the strip, or ringing it out for everything it was worth, I would spend the time to make this carb work. There is no doubt that if I could hit the sweet spot on all the marks, it would be a hit. But that's a big IF. The question is, do I have the time, money, or patience for a couple more cfm's ?
At this point, the answer is no. I will put this carb back on the shelf.

The winner in this shootout:
The Ede 650cfm Thunder Series. This car hits all the marks, on a Mopar small block. Out of the hole, midrange, top end.
Yes, I did spend time tunning it, but not much. All stock jets, rods,springs. The tunning was in the timming, vac advance, and a/f. This Swinger is basically a stock 340, with a cam, and intake. And I have said it before, if you are not careful, it will put the smackdown :elmer:
Now its time to put the 650 back on.
If only we could just leave well enough alone. :)

This is an open discussion. Any and all feedback welcomed, and appreciated.
So let it rip guys/girls!!!


IMG_20140423_205422707_HDR.jpg
 
Last edited:
I've moved on from eddelbrock carbs but out of all of them the 800 worked great on my old mild 360.
750 just felt flat compared to the 600 and 800.
 
i have used edelbrock 600, 650 Thunder and 750 ( i believe i tried an 800 as well) on many 340's
... the 600's always worked great but the 650 is by far and away superior to the other 2 for street driven cars.
 
The rods came up too early, so you need to play with the step up springs.

Mostly though, the eddy 750/800 ootb are problem carbs. Always a lean/flat spot.
 
I've run 12.6 @ 107 in an early valiant with a modded 600 Eddie with no fuel pressure during the run.

They are a good carb but most will never spend the time to get the best out of them.
 
-
Back
Top