Probably for the best. lol
What Carb for Poly Stroker
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Probably for the best. lol
That's great info Geoff and thanks but are we really comparing apples for apples here? These differences were solely due to the carburetors that the cars were running? Different cars, different engines.
The relevance to "losing tune after hard use" doesn't apply either. They didn't have an Edelbrock AVS2 650 on the cars in these tests from 1971 or whenever.
My Holley 1850 has been on the car for 4 years and hasn't needed any tweaking, except bigger jets when I got the headers. It drives to Willowbank Raceway (1 hr 30 mins), runs 5 or so passes, drives home again, doesn't lose tune.
I'm not against the Edelbrock in any way, I'm just trying to get objective information without clouding the issue.
I've been looking at this Brawler, 680cfm vac sec as well. Looks kinda cool, wonder if it performs well too?
QBR-67317 - BRAWLER 680 CFM BLACK W RED VAC SEC AUTO CHOKE
66 Sat,
You choose what you like. I have been doing this for 50 yrs. Yes, not an apples to apples comparison. The Charger v GT test pitted a 625 cfm carb against a 830 cfm carb. The extra 200 cfm didn't do much, as the GT was slower in acceleration. During the muscle car era, 4 bbl Chrys cars were head of the pack for performance.....& they had AVS or AFB carbs.
When the popular small blocks were tested in 1969 to see if their developed HP matched the adv hp, only one engine did: the 340 & it made 20 hp more than adv!!!!!! Nearly 300 hp with a little 625 AVS, factory exh manifolds. The Ford 351 made the lowest hp & guess what carb it had...
You choose what you like. I have been doing this for 50 yrs. Yes, not an apples to apples comparison. The Charger v GT test pitted a 625 cfm carb against a 830 cfm carb. The extra 200 cfm didn't do much, as the GT was slower in acceleration. During the muscle car era, 4 bbl Chrys cars were head of the pack for performance.....& they had AVS or AFB carbs.
When the popular small blocks were tested in 1969 to see if their developed HP matched the adv hp, only one engine did: the 340 & it made 20 hp more than adv!!!!!! Nearly 300 hp with a little 625 AVS, factory exh manifolds. The Ford 351 made the lowest hp & guess what carb it had...
Headintheclouds
Well-Known Member
Does it have to be a carb? I'm seriously looking at a Holley Sniper 2 EFI for my Poly 318. Very little feedback on them other than installation instructions since the release this Summer so I'm hoping they might have fixed most of the issues the original had.
Dale Davies
Well-Known Member
The engine now has 354 inches I take it. Now the original carbs on the 315 or 318 would have been a Carter 2 barrel or possibly a WCFB or an early AFB.
Your main use intention is street driving, so IMHO you would be best served using an Edelbrock AVS2 650 carb. On the street you will see better response and fuel economy. Now that will mess in Rusty's Corn Flakes, and I have no interest in if that occurs clockwise or counter clockwise, as I do not intend to offend. A double pumper Holley was designed and intended for race use. The double pump shot helps response on an engine with a lot of cam and carb get through the stumble on mashing the throttle to the floor.
Yes the Holley 750 or the AVS2 800 are most likely to give better times at the strip, but economy will tend to suffer. The AVS2 not as much as the Holley. Yes I know you can tune for mileage, but the reason for the big carb is track time.
Racers use the Holley because it is quick to change tune at the track. Between 750 CFM carbs between Rochester, Carter/Edelbrock or Holley, the Holley may flow slightly more air.
For Holley carbs tuning you get the Strip Kit with a selection of jets and air bleeds to tune for atmospheric conditions at the track.
Rochesters have been more difficult to get jets and metering rods for as they were more intended for OEM use, and tuned for that application. Since the introduction of the Edelbrock Quadrajet series, they have calibration kits for them.
The Carter/Edelbrock AFB and AVS carbs have calibration kits available. One nice advantage with these is that the tune can frequently be adjusted with primary metering rods which can be changed without removing the carb cover. Just remove the air filter housing and the metering rod and piston covers with one screw in each. No fuel spilled.
The 800 AVS2 can be tuned easily to give street and race performance, but I would urge caution about over carbing a street driven engine. Again, on the race track is one thing but how much power do you really give up.driving on the street.
As enthusiasts we need to be responsible. Our hobby is under attack and we do not need to toss nitro on that fire. Doing burnouts, fishtailing and drifting with lieberloon wokie tokies watching on the sidewalk, is not a service to any of us. To the police and law makers they see no difference between any of us. Similar was the impression of motorcyclists. Some thought if you were riding a motorcycle your mindset had to be to come and rape their daughter or wife, so they would try to run you off the road.
I would chose a bit less power at the track as you give up basically nothing on the street.
Considering that a carb is a quick and simple component to change, you could run the 650 on the street and swap on the 750 or 800 for track days. Run what you have already in the shop.
At this time it is not wise to spend money unless you have to. I hold minimal faith for a positive direction of the world over the next 5 years to 10 years.
Dale Davies
Well-Known Member
The difficulty with the Thermoquad aside from age is that like the Quadrajet, those big secondary throttle plates will not clear the factory manifold. True that a carb adapter could be purchased if there is enough underhood height.
IMHO for mainly street use, go with the AVS2 650. Nothing wrong with the Holley style carbs. My 289 2V did require a bowl gasket every spring or at minimum tighten bowl screws as the gasket dried and shrank over the winter. For me the Edelbrock performer 600 on an Airgap manifold cured that issue. I believe there are better gaskets available now for the Holley float bowls.
Dale Davies
Well-Known Member
That is a rare piece. Carter also made some like that for the Pontiac race program. Rare as the Autolite Inline 4V carbs.
Dale Davies
Well-Known Member
The Edelbrock carbs have a dual bolt pattern, so should ba a dropon that way. The AVS2 650 should be a bolt on. The AVS2 800 likely requires opening the secondary bores in the manifold.
A young lady that lives here has a poly engine with a 6 pac her Dad built. Otherwise it is stock.
Last time I checked, which was like Yesterday, all the new AVS2's have annular boosters...that engine will be fine with the 650.
I am a TQ fan, as many on this forum know. I purposely did not recommend it for the reasons Dale has described above. The adapter reqd to fit to the Poly intake would kill a lot of flow & probably cause turbulence that would affect cyl-to-cyl distribution.....& reduce
power.
From day one in 1957, Carter very cleverly with their 4bbl carbs, made models with small primaries & larger secondaries. Small pris for response & mileage, the bigger secs for power. A no-brainer isn't it????
When Edel decided to get into the carb business, they reproduced the Carter AFB/AVS design.
Reason could have been because very man & his dog were already making 'better' Hs.....
A little known FACT is that Edel used to sell H carbs looooong before they started reproducing the Carters.
power.
From day one in 1957, Carter very cleverly with their 4bbl carbs, made models with small primaries & larger secondaries. Small pris for response & mileage, the bigger secs for power. A no-brainer isn't it????
When Edel decided to get into the carb business, they reproduced the Carter AFB/AVS design.
Reason could have been because very man & his dog were already making 'better' Hs.....
A little known FACT is that Edel used to sell H carbs looooong before they started reproducing the Carters.
I ordered a 650 AVS2 yesterday morning - should be here in a few days. I've been reading about the fuel pressure needing to be between 4.5 & 6 psi. I have no idea what my factory style mechanical pump puts out. I might try it and see how it runs before I buy a regulator. I also have to buy (or I might make one) a timber adapter to replace the aluminum one that I have at the moment. Apparently the Edelbrock won't like the heat transfer from the cast iron manifold to aluminum spacer to aluminum carburetor (I have no issues with my Holley in this regard).
I'm very excited to see how good the throttle response is going to be after hearing all these good things about it.
I'm very excited to see how good the throttle response is going to be after hearing all these good things about it.
Mate,
You will be veeeeeeeeeeeeeeeeeeeeeeery happy. You will NOT need a reg. The quoted fuel pressure figures by Edel are for the purpose of establishing the fuel level [ 7/16" ].
Every carb is designed to work with a specific fuel level in the fuel bowl that is relevant to the discharge point at the booster. Called the spill height, it is usually between 1/4 -3/8", ie the bottom of the booster discharge is above the fuel level in the bowl by that amount. Reducing the spill height [ raising fuel level ] richens the fuel level slightly & vice versa. One good feature of Holleys & clones with sight plugs is setting the fuel level.
Fuel pressure, needle & seat diameter affect the fuel level.
When Edel copied the AFB/AVS they did not change the fuel inlet system in any way shape or form. All of the parts are interchangeable: needle & seats, floats.
Carter produced a chart showing float adjustment for as high as 10 psi [ see below ]. I have run Carter carbs with 10 psi of pressure, zero problems. The Edel will also have no problem with that much pressure because they come with small 0.093" n/seats; smaller n/seats control fuel level more accurately.
Your pump is problaby outputting 4-8 psi & I would just run it....No reg needed. Don't forget THAT pump was used to feed Carter carbs....& had no problems doing it.
Every Edel carb I have encountered needed the float level to be adjusted. I suspect rough handling during the long journey is the reason.
So I recommend you check the setting. You will NOT need any gaskets if you are careful. Take pics/drawing of the linkages. If you lose a circlip I can send you some spares. Give me a holler if you get stuck.
You will be veeeeeeeeeeeeeeeeeeeeeeery happy. You will NOT need a reg. The quoted fuel pressure figures by Edel are for the purpose of establishing the fuel level [ 7/16" ].
Every carb is designed to work with a specific fuel level in the fuel bowl that is relevant to the discharge point at the booster. Called the spill height, it is usually between 1/4 -3/8", ie the bottom of the booster discharge is above the fuel level in the bowl by that amount. Reducing the spill height [ raising fuel level ] richens the fuel level slightly & vice versa. One good feature of Holleys & clones with sight plugs is setting the fuel level.
Fuel pressure, needle & seat diameter affect the fuel level.
When Edel copied the AFB/AVS they did not change the fuel inlet system in any way shape or form. All of the parts are interchangeable: needle & seats, floats.
Carter produced a chart showing float adjustment for as high as 10 psi [ see below ]. I have run Carter carbs with 10 psi of pressure, zero problems. The Edel will also have no problem with that much pressure because they come with small 0.093" n/seats; smaller n/seats control fuel level more accurately.
Your pump is problaby outputting 4-8 psi & I would just run it....No reg needed. Don't forget THAT pump was used to feed Carter carbs....& had no problems doing it.
Every Edel carb I have encountered needed the float level to be adjusted. I suspect rough handling during the long journey is the reason.
So I recommend you check the setting. You will NOT need any gaskets if you are careful. Take pics/drawing of the linkages. If you lose a circlip I can send you some spares. Give me a holler if you get stuck.
Yeah. Like the super rare Cross Boss dual inline four they offered. This would look good on a poly. lol
Dale Davies
Well-Known Member
Annular primaries but regular secondaries. With the Edelbrock AVS2 models they build them with secondary venturis which the AVS do not have.
Edelbrock also has their new VRS 4150 series modular carbs. These also have annular boosters. The carb is also 1/2" taller giving a longer venturi length which may also contribute to better fuel atomization and thus vapourization. Sizes in 650, 750, 850 and 950 CFM ratings.
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If we're keeping score, my vote is for the AVS2 650 for the reasons others have put forward.
As for the question quoted, I wonder if it matters whether the individual is from North America or 'down under'? What about a North American in Australia and vice versa? Or is it food dependent (Vegemite is just plain nasty)? I think I've just found my next research project to scam the government out of another bazillion dollars. Thanks guys!
I've heard vegemite is nasty, but I've never tried it. My son is living in Australia now and says they certainly have some "different" food. He does all the cooking in their household. He whooped up some of my wife's sausage gravy and biscuits not long ago and he said they oinked it down like they hadn't eaten in days. They'd never had it.
He's in East Bunbry, wherever that bees.lol
Dale Davies
Well-Known Member
Too bad we did not know back then what we know now. Just as I started working you could go into a Ford dealer and order one like shown or the single carb. For Mopars, a Challenger TA or Cuda AAR. Put in storage on blocks. Or one of the wing cars. A couple of those now with basically 0 miles and retirement would be a bit easier.
I know, right? Too bad wisdom usually only comes with age. lol
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