Edelbrock Carb; 500 or 600cfm?

[WarrenC]

I've read a lot of posts here and other places about this, but I'm still somewhat confused. To me, it sounds like the 500cfm will work better on my totally stock 289 in my 67 GTA. But I can buy the 600cfm for less, which doesn't make sense to me. Also, should I get the manual or electric choke? Besides the choke, it seems that the carbs are jetted differently.
I want the most performance I can get without sacrificing driveability and reliablility. Economy? Who cares.
Any advice is welcome. Thanks!

 

[65 fastback]

WarrenC - I think the GTA came stock with a 4 bbl and dual exhaust, correct me if I'm wrong. If that's the case and you're just swapping carbs, go with the 500 cfm. If your going to swap the intake and go with headers and 2-1/4 dual exhaust, you might go to the 600.

In either case go with the electric choke.

Tim

 

[302 coupe]

there really won't be any difference between the two. A 500 may be all you need technically, but it will run just fine with a 600. It won't run rich or anything. An Autolite 4100 would be better than either of the edelbrocks though.....

 

[blown65]

Ya, I agree, a 600 should do ya fine, and the difference if any would not make it worth the cost difference. Buy a K&N filter or some other cheap power boost for the diff.

 

[Mark66p]

500

 

[WarrenC]

Thanks for the input. I'm curious about the post that says the stock Autolite 4100 would be better, though? So there isn't anything to be gained by swapping carbs? No need to throw money at it if I don't need too.

 

[WORTH]

If the carb you have is good, keep it.

 

[302 coupe]

the 4100 is a fine piece, if thats what you already have-stick with it.

 

[WarrenC]

Actually, I think mine came with a 4300 which should be quite similar.

 

[rbohm]

the 4100 is the best carb for a stock or nearly stock application, the 4300 requires a bit more tuning but is also very good. as for the aftermarket carbs, the 500 edelbrock is all you need untill you get to the 350hp level, then go for the 600. as for the 600 not running rich out of the box, YES THEY DO. i know, i have one on my grand marquis, and it needed to be jetted down, as well as changing metering rods to get it to pass emissions in az, and still run smooth. aftermarket carbs are going to run a bit rich out of the box as they manufacturers do not know what your combination is, so they tune them rich to prevent someone just bolting a carb on an burning a piston, and sueing the manufacturer, because they didnt tune the carb right.

 

[Jonstantine]

as someone who currently is replacing a 600 cfm edel with a demon...

get the 500cfm carb
even though the 600 is cheaper, as rich as it runs you'll need a tuning kit for sure which is 40 bucks... save yourself the trouble

the 600 bogged my motor to 2.55 60' times (mechanical secondaries)... if you have any doubts, call edelbrock
they'll probably tell you 500

but hell, you can get a road demon for 50 bucks more...

*if you must have a 600... ebay has them used for cheap

 

[1320stang]

Jon, what are you doing up so late? Or is it early?

 

[68RCodeConv]

I recommend 500 cfm - more details inside...

Back when I was in high school we had five (5) 1967-68 Mustangs with 289 engines. The engines were all stock internally. Some were originally 2V and some were 4V. In every case we replaced the 2V intake with a 4V. On one car we used an Edelbrock F4B intake (similar to a Shelby intake) and on the others we used the stock cast iron intake. We ran 4100s (the small 480 cfm version), 4300s, and Holley 600 carbs. The Holley ran like crap - way too much carb out of the box. I didn't know how to tune a Holley so I got rid of it. The 4300 ran OK but it was tempermental and hard to rebuild. The 4100s ran great - wonderful secondary action, easy to rebuild, no leaks.

Based on that experience when it came time to choose a carb for the 289 HiPo in my 67 GT350, I chose a 500 cfm Edelbrock. It's been a great carb. I have not had to make any changes to the factory tuning and it has wonderful low-end driveability and pulls hard all the way to 5000 rpm. Since stock A-code 289 cams/heads pretty much stop making power above 4500 rpm, what else do you need? Plus you don't have to worry about the gaskets drying out and leaking. I let one sit for 12 months without running it. Started right up with no leaks. Try that with a Holley 1850.

 

[Mustang196t8]

The 4100 is good, the 4300 is a turd.. it came around in '67-'68 to 'replace' the 4100 for emissions needs..

For a stock 289 I'd say a 500 would be better, the 4300 that came on stock 289/302's flowed 441cfm IIRC...

The difference between a 600 & 500 Edelbrock (or Carter) is the secondary venturi size, so the extra cfm doesn't matter until you stomp on it.. the venturis are also removeable, so you could feasibly change them later (if they sell them individually, not to sure on that one..).. Although the calibration (metering rods,jets,springs) will probably be a tad leaner for the 500 vs. the 600.

The electric choke versions are calibrated more for economy(mpg), and the manual choke versions are calibrated more for performance (richer).. according to the catalog.

I run a 600 Holley vac sec on my internally stock 302 in my '68, and it runs fine... it runs a HELL of a lot better than it did with that 4300.. all the way around, power, mileage, everything.. .I even ran a 600 cfm 4100 of my '65 Galaxie 390 for a little bit, and the Holley would kill it big time.. I've never had any 'leaks' with the Holley.. and my car has been sitting for about a year and a half, I start it up once a month, and I have had NO probs with leaks... That 4300 sure did leak tho, like a damn GM quadrajet...

 

[Jonstantine]

Jon, what are you doing up so late? Or is it early?

im a weekend/nightshift security guard for a juice company in my hometown

 

[WarrenC]

OK, I settled on a 1406 Edelbrock 600cfm electric choke-mostly because it was much cheaper than a 500cfm. If it's too rich, I'll have to re-jet it but it will still be cheaper.
Next question: What will I need to make this work? Will my stock linkage hook up? Kick down lever? How about the air cleaner? I have a stock one. How about the choke hookup? It looks like the Edelbrock has an electrical hookup, whereas my Autolite looks like it has a copper tube hooked up to it, taking heat from the exhaust manifold I think.
If the Autolite was a 4100 I think I would have stayed with that, but it seems the 4300 is more problematic. And so far it has lived up to that expectation.