500cfm Summit carb on 318

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gtxdude

gtxdude

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Dropped a 500 Summit carb on my mild 318 to try out. When I accelerate aggressively around 3200 -3300 rpm it seems to be starving a little. If I back off it's fine and can cruise down the road with no problems. Adjusted fuel pressure up a little from my Eddy. Not sure if changing secondary springs would help or not. Probably go back to my Eddy but I thought I would play around with this a little. Any thoughts, throw them out there, thanks
 
Can you maybe post a link to it so we can see what style of carburetor we're dealing with here?
 
Summit carb, based on the Holly's I believe. Vacuum secondary

1690747612259917377108698148131.jpg
 
Ok Summit's version of the 4010 and 4111. I would try raising the rear float level a little bit and see if that helps.
 
4mulas said:
Just like anything it probably needs to be jetted.
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Agree. Maybe they stock jet kits for those.
A friend of mine has used a few on customer builds and is happy with them.
Basic 302 Ford and 350 Chevy street rods.
 
4mulas said:
Just like anything it probably needs to be jetted. But 500 is maybe a tad small for 5.2 litre motor
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There's a carb shop in town and he keeps telling me a 500 is to small, but I don't listen :)
The best this car ran was when I had a Eddy 650 AVS 2 on, great acceleration, ran great. But I kept thinking I don't need a 650, I rarely get over 4500rpm. All the calculators say 500cfm or less is plenty, but none of them really ran that well or got better mpg. We do a lot of cruising so (Route 66 couple years ago) so I'm always looking for something to get better mpg. I think I've exhausted all my options out there, I'll play with this one awhile and decide what to do over the winter. :rolleyes:
 
The 500 is not too small for a stock or mild 318. It's spot on.
 
gtxdude said:
There's a carb shop in town and he keeps telling me a 500 is to small, but I don't listen :)
The best this car ran was when I had an Eddy 650 AVS 2 on, great acceleration, ran great. But I kept thinking I don't need a 650, I rarely get over 4500rpm. All the calculators say 500cfm or less is plenty, but none of them really ran that well or got better mpg. We do a lot of cruising so (Route 66 couple years ago) so I'm always looking for something to get better mpg. I think I've exhausted all my options out there, I'll play with this one awhile and decide what to do over the winter. :rolleyes:
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The best it ran ever was with a 650 eddy, so you’re going to let it run like crap and stew over what to do and keep using a 500? That doesn’t make sense. Your car, 4 bolts and a fuel line could fix it, but why don’t you call it quits for the rest of the season and decide over the winter what to do……..
 
If you follow my posts, I like putzing around with stuff. Try something doesn't work go back to what I had, maybe later I'll try something else later. If I get hung up I throw it out there for some feedback and comments to see if I can make it better. I won't run a crappy carb rest of summer but I might have some fun with this one before switching back ( or not) Keeps me off the streets at night :steering:
 
RustyRatRod said:
The 500 is not too small for a stock or mild 318. It's spot on.
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From what you have stated above and the type of driving you do I will agree.
Yes you will get better performance with a larger carb at high rpm full throttle.
Also if any work is done to the 318 if you are looking at performance.
A stock 318 2bbl is maybe 350 cfm .
Now this is just me. Not wanting to start a fight. My favorite carb is the Edelbrock 500 cfm.
The carb for general use. I used a 500 on engines as large as a 451 stroker. Street driven.
gtxdude said:
Keeps me off the streets at night :steering:
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I say keeps me out of bars and chasing wild women !!
 
thats a dang good carb when dialed in! ran a holly 750 version back when thay built them on a hot 340 for years, never had to mess with it always run well!
 
Chasing women, bars, cruising at night is what it’s all about! That’s why I was cheeky about my carb comments and think you should put back in what you know works best and drive!
just my opinion…. Good luck
 
Darter6 said:
From what you have stated above and the type of driving you do I will agree.
Yes you will get better performance with a larger carb at high rpm full throttle.
Also if any work is done to the 318 if you are looking at performance.
A stock 318 2bbl is maybe 350 cfm .
Now this is just me. Not wanting to start a fight. My favorite carb is the Edelbrock 500 cfm.
The carb for general use. I used a 500 on engines as large as a 451 stroker. Street driven.

I say keeps me out of bars and chasing wild women !!
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I understand what you're saying completely. However, how many people spend their time in a street car more than 50% of the time 4000 RPM of higher? That's where a larger carburetor will be of benefit for a smaller engine. I'm not trying to start a fight either, but that's a 100% fact for a street car. This is a street car we're discussing, is it not?

I want to come back and add, I agree with your assessment of the stock 2 barrel. 350CFM is probably right in the ballpark. So, since we agree on that, then that means a 500CFM four barrel is a pretty healthy upgrade on a mild or stock 318. Right? RIGHT? lol We're simply so USED to reading and hearing anything 600CFM and above relating to "performance" that anything smaller sounds whimpy, and that's not necessarily so.
 
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4mulas said:
Chasing women, bars, cruising at night is what it’s all about! That’s why I was cheeky about my carb comments and think you should put back in what you know works best and drive!
just my opinion…. Good luck
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LOL
 
The upper quote was for gtxdude.
The lower is for you Rusty .RIGHT ! I completely agree with you. I do 99% of the time with your posts.
 
gtxdude said:
If you follow my posts, I like putzing around with stuff. Try something doesn't work go back to what I had, maybe later I'll try something else later. If I get hung up I throw it out there for some feedback and comments to see if I can make it better. I won't run a crappy carb rest of summer but I might have some fun with this one before switching back ( or not) Keeps me off the streets at night :steering:
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Try jetting the secondaries up a few notches (if available). That way you will hopefully have some extra punch when you floor it, and you'll have better economy when just cruising. I have followed a lot of your posts. I know you are a putz. Oops, sorry. I meant to say I know that you like to putz around. :lol: :lol:
 
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