Carburetor suggestions for 318

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scott2683

scott2683

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I've got a 71 with the factory 318. I'm running KB high compression pistons with mid 80's 1.60"/1.88" heads. It has the xe268h comp cam.

I currently have an edelbrock 1406 600CFM carburetor with an edelbrock performer intake on the car. I'm not 100% impressed with the performance of the carb, I was wondering what you guys would recommend? Could I go larger? Is there a better application out there for me? The car is mainly a driver, I like to get on it from time to time, but i just want something thats good for the road, I'm not concerned with gas mileage.

I bought the carburetor new, and it only has maybe 1000 miles on it.

Thanks for the help guys!!
 
I was going to suggest the exact set up you have.
What is it doing/not doing,that you don't like. Your car should be able to
light em up with that combo.
 
670 Holley Street Avenger.
 
Sometimes I get a sputter on acceleration, Its seems to be running a little rich. It may just need a little more adjusting.

I'm not overly familiar with tearing into a carb, I can tune one pretty decent with the adjustment screws, but thats as far as my knowledge goes.
 
The owners manual for that carb is quite comprehensive, Read and heed. What about the rest of your combo? If you have mid 80's 360 heads, 2.76 gears and a factory torque converter, the carb isn't your limiting factor. A 1406 should be pretty darn close out-of-the-box for your combo.
 
Gears are 3.23. the torque converter is factory, but the transmission has been rebuilt with a shift kit. I bought the heads from Aerohead racing. The heads work pretty decent but I'm sure I'll upgrade them at some point. The car isn't sluggish or slow, I just wondered if I could optimize my performance and get rid of some of the hesitation with a different carburetor. I'll visit the edelbrock website and read the owners manual.
 
For the most part, i'm a Holley guy. I still think you can get what you need with that carb. Timing will play a roll also. 15 to 20 degrees intial will really make it drivable depending on your exact compression ratio.

If by chance you don't have this info.....it will help you understand the tuning on a Eddy carb....
[ame]http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf[/ame]
 
scott2683 said:
Thanks for the info Rick, I appreciate it!!
Click to expand...

Your welcome Scott. I should mention that if the car likes more initial timing, which it may, you'll have to check the total timing to make sure you're not much above 34/36*. If that's the case, you may have to modify the distributor to limit the total timing. Good luck, it sounds like a nice combo. :thumleft:
 
OldmanRick said:
Your welcome Scott. I should mention that if the car likes more initial timing, which it may, you'll have to check the total timing to make sure you're not much above 34/36*. If that's the case, you may have to modify the distributor to limit the total timing. Good luck, it sounds like a nice combo. :thumleft:
Click to expand...
Thank you sir! I'll recheck the timing and tinker around with everything when I get a free afternoon!
 
Those carburetors respond to a really accurate metering rod, step up spring and jet set.

If you hit the top with the torx screwdriver and get new ones, you should be good to go. I don't know what part of indiana you are in, but you may have to jump down one set of jets in the primaries and see if you can get it tuned for about 1500ft elevation in primary and secodary.

It may not make much of a difference, but there are a lot of things that can change tune. The best way to tune a carb is by Air/Fuel ratio readings. An emissions test is a cheap way to get PPM readings from your setup to tell you where you're at. I'm going to use an O2 sensor in the exhaust and plug it after tuning.

If you can't get it to run to your liking, look at a Street Demon. That's also what I am running.
 
YouTube has a couple good videos for the initial setup. Check it out.

I always like to bench test them,to see what I'm starting with. Starting with the factory jets,rods,springs is the best way to start.

There is a pump shot arm with 3 holes. Factory setting is the middle hole. You can get a bigger pump shot by using the farthest hole from the base. I've always had the best luck with the middle hole.

I have always had the best luck with the (orange) stock step up spring.

Get the A/F and idle set right first,and then you can get out there and play with the timing.
 
OldmanRick said:
Timing will play a roll also. 15 to 20 degrees intial will really make it drivable depending on your exact compression ratio.
Click to expand...

Best comment in the thread. Timing FIRST!!!

Simple test, start the car, get it warmed up, grab distributor and give a light twist CCW. If the engine picked up rpm, it wants the additional idle/initial timing. Reset the idle speed.

The range Rick mentioned is where I would search to set initial on this engine. It's a safe range and won't tax the starter/battery. If you used the total timing method, that's sometimes a big issue because it totally disregards where your initial timing setting.

Don't throw money at something that quite frankly... money can't fix! IMO, it's likely a tune up issue which can be fixed cheap.

Good luck with it.
 
Thanks guys for all the good information! I really appreciate all the advice!
 
Many years ago I ran one on a 318 with the same intake / similar cam, tuning made a huge difference. I jumped the gun and put it on out of the box with only air mixture adjustment done. Ran sluggish. Went back and went thru the instructions on how to set it up and the difference was very noticeable. Very good street carb.
 
They always say Holley for performance, but timing and getting your squirter working right are the 2 big ones. Listen to cracked, and old man rick they are both great at giving accurate advice and will give you all the help you need, I ran your set up a couple years ago with 291 gears 318 600 holley and it would torch the tires. Be patience and listen to the pros. If you later change carbs the 670 holley is nice. Im now running a 770 street avenger on my 360 and love that thing, they say bolt on ready to run but you must fine tune any carb to your liking.
 
Timing and carb tuning are key. Especially the timing. There was an old mopar action article where you heated up the slots on each end of the dist where the weights ride, and hammer on a 3/8th bolt sideways to shorten up the travel. Then you ground it back flat. Its possible to get something like 20 degrees in the distributor with that method. I actually did a toyota 22r dist that way and it worked well. And I was amazed by how much power I was throwing away from the lazy timing curve.

Also, be sure that you do all these adjustments and checking and such with the vaccume advance disconected and plugged.
 
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