Which Edelbrock Carb 500 or 600 cfm?
 

I have a little 283 bored .40 over with an RV cam. I currently have a Holley Street Avenger 570 cfm that I cant seem to get running right.

I have always liked the Edelbrock carbs but not sure if I should go with 500 or 600 cfm?

Thanks

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Re: Which Edelbrock Carb 500 or 600 cfm?
 

I like seeing trucks with their little 283s still in them. I have a replacement 283 bored .30 over just waiting to get dropped in. I have a 600 cfm Edelbrock sitting on top right now. I don't know the answer to your question but looking forward to the answer.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

Everyone will have an opinion on this subject but mine is that a 500 will put out all the fuel you can burn without rich type smoke. I had a 780 on a 454 that wasn't stock but it wasn't a radical engine either and I had to choke the jetting down quite a bit to get it just right. I'm building another truck now and going with a 383 and I'm just going with a 600 holley. A lot of people will argue with me but I personally like the holleys because I growed up playing with them and can work on them easier.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

If you go to Holley.com there is a carb sizing tool. It will recommend Holley carbs, but will also make recommendations on cfm, etc. When I used it for my bone-stock 350, it came back with 400 cfm.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

That's where a quadrajet makes sense. Small primaries for good street manners and economy and large primaries for power when you want it.
Cool truck you've got there.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

If it is just a cruise around truck then would recommend the 500, better street manners, but if your an RPM kind of guy and like to push it then would step up to the 600, either way can't really go wrong though. My choice of a dependable carb.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

My first thought is what's wrong with the holley carb you got?
Changing carbs might only make your wallet lighter.
Tell us what it's doing.
And btw your heater hoses are on wrong. Intake to the bottom of the heater core, top of core back to the pump.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

The deeper I get in to it the more things I find wrong but I guess I cant complain since the truck was free.

When I got the truck the carb was black inside and it was running rough and it had backfired a couple times. I reset the timing to 9 degrees TDC and adjusted the idle. Now no more backfires.

Now when I put the truck under load after it has been running for a couple mins it wants to stall. I have to really rev it (2,000 rpm) to get it up a hill. It sounds like its sucking a lot of air. I don't have to rev it as much if I let it sit and warm up for awhile. It has a electric choke. I found the Holley manual online and was going to read it tonight.

Thanks for the info on the heater hoses.


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Re: Which Edelbrock Carb 500 or 600 cfm?
 

Sounds like the normal lack of initial timing scenario.
Did you set your initial with the vac line to the dizzy plugged?
If so bump it up to 14 degrees. If it gets better then try a couple more degrees at a time until it's hard to start when hot or it pings.
Make sure you turn your idle speed down as low as possible when you set your timing.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

Yeah I set the initial timing with the vac line plugged. I will try it again and see where its at. The timing marker on the timing change cover only goes to 12 degrees.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

Ok so I up the timing to 13 or 14 degrees TDC. Not sure since its off the chart. It does seem to run smoother. I also adjusted the electric choke speed faster. So now it jumps up to 1,000 rpm when I fire it up. Before It would stay low at 500-750 rpm and I would have to keep it going.

Do I need to be nerves having the timing adv so much? I know the old saying is "running lean is running mean". Also I have a noob question. How do I know when it starts knocking? Is it loud? Will I hear it with my head under the wood or would I need to drive the truck?

Thanks again for all the help.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

I have had lots of people come into or call my shop and ask carb questions, more so back when I was real big into the hot rods motors and drag racing and bunches of power and stuff like that. I had a answer for them that I go by on my rides. I your gonna ride around and every once and a while flog it or drive it like you stole it, put on a Edelbrock. If your gonna race and do some riding around every once in a while get a Holley. Now many will disagree and proclaim I drive 500 miles a day with a Holley well ok. You can but in general the Edelbrock is more of a set and forget type carb. If you put on a good glass filter close to the carb and keep the fuel pressure turned down to no more than 5.5 or else the pressure might override the needle and seat and cause flooding that is the main complaint from the edelbrock carbs. Go with the 500 cfm

Re: Which Edelbrock Carb 500 or 600 cfm?
 

600 cfm is more than enough mathematically you would never use it to its full potential with any small block it will always be enough for it no matter what you do to that engine you won't ever use any more than 536 cfm on a small block chevy engine

Re: Which Edelbrock Carb 500 or 600 cfm?
 

500 is plenty. If you've got a spread-bore or dual-pattern intake I'd put a Q-Jet on it. Helps if you have someone good at tuning them, but there are only 3 living people left that can do it :-) Otherwise I've had good luck with the Edelbrock (Carter style).

Your open element air filter will make cold start drivability more problematic, but as long as the choke is set right you shouldn't have to two-foot it (my pet peeve).

Re: Which Edelbrock Carb 500 or 600 cfm?
 

Just listen for a rattle sound like rocks in a metal can. You will hear it from the drivers seat. Best way to test for pinging is when you get into high gear at a slow speed, step on the loud pedal without shifting down a gear. If it rattles, pull it back a couple degrees.
Every motor combo is different. I ran an aluminum headed 350 with 22 initial, 12 in the dizzy and 10 from the vac pot.

Re: Which Edelbrock Carb 500 or 600 cfm?
 

I have a 1406 Edelbrock on my 396 that was on the truck when I bought it in 2001. I have never had to touch the carb and it works as its supposed to whether I'm leisurly driving at 30mph or getting rubber betwen 1st and 2nd ( the truck has a TH 400 trans ) so my 2 cent is bolt on on the Edelbrock and forget it.