slappo
New Member
I have an older edelebrock on my 318 poly (sitting on weiand high rise manifold). I'm wondering if if would be better to rebuild this one, update to a newer edelbrock or switch to a holly.
Carb recommendations
- Thread starter slappo
- Start date
Personally I am a big fan of the new Eddy AVS2 Carb. Has a nice spray pattern and is easy to setup. I am using it on a couple of cars with good results.
SportFury70
Senior Member
I 2nd that Eddy AVS, they’re our new carburetor of choice now if we needed one. We got 2 of em and they run great on the cars, and we (like you) got Weiland intakes on both of ‘em too. The other option I would say would be a Demon.
Send your carb off to @Dana at Woodruff Carbs for rebuild.
If it is not a restoration numbers carb and you're not rebuilding the carb yourself, then I would buy an AVS2. The cost to rebuild the old one will be about what the AVS2 will cost at Summit.
Northcoast300h
Active Member
I just wanted a carb that I could set, forget, and run great forever. After playing with Holleys, Carters, Edlebrocks on previous cars, I went with a Thermoquad, rebuilt by Demonsizzler. This was 20 yrs ago. Sure that first year was a pain to dial it in and I had to modify linkage to install it, but Thermoquad's are engineered better than other carbs (except if racing).
Thermoquad is the only carb I've ever had where I can start it cold and go. No warm up needed. Its fuel circuits are engineered not to to stall, no rough idle, no vapor lock even when weather is over 100F due to its phenolic fuel bowl. I can panic brake and go around turns quickly without stalling. With smaller primaries, its better on mpg than Holleys and others. With larger secondaries, (1000cfm), acceleration is good too.
However its not all great. Thermoquads secondaries open up slower than others so you don't feel that cool jolt when you hit the accelerator. Its not a big difference in acceleration but I noticed the previous Holley was a little quicker off the line. If you adjust the secondaries to open too quickly, then Thermoquads turn into "Thermobogs" so these aren't meant for racing. However if you want to go fast...then just go buy a Tesla.
Thermoquad is the only carb I've ever had where I can start it cold and go. No warm up needed. Its fuel circuits are engineered not to to stall, no rough idle, no vapor lock even when weather is over 100F due to its phenolic fuel bowl. I can panic brake and go around turns quickly without stalling. With smaller primaries, its better on mpg than Holleys and others. With larger secondaries, (1000cfm), acceleration is good too.
However its not all great. Thermoquads secondaries open up slower than others so you don't feel that cool jolt when you hit the accelerator. Its not a big difference in acceleration but I noticed the previous Holley was a little quicker off the line. If you adjust the secondaries to open too quickly, then Thermoquads turn into "Thermobogs" so these aren't meant for racing. However if you want to go fast...then just go buy a Tesla.
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70bigblockdodge
Old Man with a Hat
Agree with Thermoquad.
I can't agree with the buy a Tesla.
TQs are love/ hate if you have ever put down the miles with a good one you can really appreciate where they were going with them.
I have one on every car except my race car, and I'm putting one on my Imperial. Looking for the small version (hunting at Carlisle) I usually pass them over, but now that I have a 318 car I need one.
I agree with Big John on Woodruff's carb shop.
My son has a AVS2 on a Chevy pu that he daily drives it does okay. As usual with those Eddy carbs they are happiest with high vacuum and smooth idle. His is much better with the manual trans than it was with automatic.
I can't agree with the buy a Tesla.
TQs are love/ hate if you have ever put down the miles with a good one you can really appreciate where they were going with them.
I have one on every car except my race car, and I'm putting one on my Imperial. Looking for the small version (hunting at Carlisle) I usually pass them over, but now that I have a 318 car I need one.
I agree with Big John on Woodruff's carb shop.
My son has a AVS2 on a Chevy pu that he daily drives it does okay. As usual with those Eddy carbs they are happiest with high vacuum and smooth idle. His is much better with the manual trans than it was with automatic.
slappo
New Member
Think Ill invest in an edelbrock AVS as father day present for myself. Last question would be suggestions on the cfm size
Nothing wrong with what you have. My 600 on my 273 has been there for 10+ years and still starts and runs like a champ.
Mid70's Chrysler Fanatic
Well-Known Member
I like the 1906 AVS I put on my 440-powered ’74. Car starts up easily even after sitting a while. No hesitation and it’s as happy to go 80 mph as 60. (Haven’t driven the car in a while—it needs a whole exhaust system. But that’s for another thread.)
Northcoast300h
Active Member
A stock 318 poly max safe RPM is 6000, correct? According to the CFM formula, the most air it can swallow is 552CFM. Add 10% for to cover any carb marketing BS and its 607cfm. Add a little more for those crazy times you go above 6000 rpm and I'd say a 650 would be perfect...Who's with me!
If you do buy a new carb, Just be sure to buy the AVS 2.
NOW . . . how much time will be spent at those elevated rpm levels? Primaries sized at or below 1.69" are fine for a small motor, by observation. Almost perfect for a 360CID motor, and a bit less so for a 400CID motor. On the primaries, "size" for a 3000rpm cruise and let the WOT stuff happen as it might for the carb size.
So, the famed 0-3310 780cfm Holley, with 1.69" throttle plates, would be about 400cfm on the primaries alone. Might be too big in the total aspect, but not too big for a 3000rpm cruise, in any A or LA motor I suspect. Then tune the spring pressure for the secondaries to open only as much as needed, which they will mostly do anyway, to not over-carb the motor at WOT.
In the above CID air quantities, what level of Volumetric Efficiency is being used in that formula?
Just some thoughts,
CBODY67
Northcoast300h
Active Member
Thanks Cbody67. Whoops....I was in racing engine mode. Old stock engine VE commonly top out at 80%, so the most air that 318 can swallow at 6000rpm is 442CFM. Thanks for catching that.
Doesn't going too big on a stock engine require extensive tuning with zero or little benefit?....Rich idle, black smoke, flat spots and bogging in the midrange because of low velocity through the venturis, while at the same time lean-out at high RPM after secondaries open. Using an oversized carb not tuned properly is a mess. I think that's what happened to me when I put a 1000cfm Thermoquad on my stock 440, until I played around with changing jets/metering/tuned. It's still not as fast at WOT as the smaller holley carb that was on it before, but it works great now in every other way, so I'm happy with it.
Thanks.
The key in the 1Kcfm TQuad is only opening the secondaries enough for max power, which is NOT fully open, but only partially so. Might not look right, but otherwise is "too much" air. Primary side should be fine, though, which is where the vast majority of driving is done.
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