need carb recommend for my new 360

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screeminDemon

screeminDemon

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I appreciate your advice, before I purchase new carb.

My motor: 360 punched 30 over
stock pistons
summit cam 228 duration, 480 lift at .050
edelbrock performer intake
stock rebuilt 360 heads w 1.88 valves
headers

Thanks!
 
Thanks Jerry, I'll check out the price on that one. I've got a guy who wants to sell me a holley 650, like new, for a really good price. Do you think it would provide enough fuel? As you know, I've had a lean problem, but it may have been a bad rebuild on my current holley 600...

Also - what about vac secondaries compared to mechanical?

Thanks again!
 
I would say that depends in intended usage.

Street only? Street/strip?

Also, how much does it weigh? What gear? Stick or auto?

With that combo, I bet a Holley 670 Street Avenger would work really well, but without the other data I'm kinda shooting in the dark.
 
Street/strip? 3310 Holley.Street only?750 Eddy. Good to see you keep working on it.By the way,sell off that old Holley you have.They are damn hard to find.
 
screeminDemon said:
I appreciate your advice, before I purchase new carb.

My motor: 360 punched 30 over
stock pistons
summit cam 228 duration, 480 lift at .050
edelbrock performer intake
stock rebuilt 360 heads w 1.88 valves
headers

Thanks!
Click to expand...

edelbrock 650 avs :mrgreen:
 
Pretty much just street use. It was my daily driver before, and will continue to be my daily driver, although I'd love to be able to beat a few chevies at the stop lights.

I've got the a-833 4spd w/ ovrdrive in it with 323 gear in the rear.

thanks for your input!
 
my fresh built 360 is running a rebuilt holey 750 and im liking it
 
Spread bore vaccum secondary.600-750 max.
find a true carb guru and pay him to tune.
TQ. AVS or Holley...
You'll get great drivability and wide open punch.
And mpg..
A REAL CARB GURU!!!!
 
In short, I vote for the Edelbrock AVS style carb, but read on;


I noticed you mentioned something about running lean, which has nothing to do with carb size by tit does have everything to do with how the carb is jetted. So, any carb could run rich or lean, it's not size dependent.

A vaccum secondary carb has smoother transitions into the secondaries. A DP can be abrupt. (Not that it's a bad thing.) It should also have an edge on mileage, but that is also driver dependent. Lead foot or not.

Considering the 3.23 gears w/an overdrive trans, I myself would go for a 650 cfm carb. Maker? Your choice. I myself like the AVS style carb or TQ. Tuning them is key!

Tuning a TQ can be hard sometimes. Parts are not on the corner store shelf. I use home bent AFB rods to tune them if need be. But the nice thing is, the Performer will accept the TQ, no problem.

The smaller carb will only give up a minor and I really mean minor amount of HP only seen in the upper RPM range vs a bigger carb. (the 750 ) and no one would ever feel it or notice it unless your at a track being timed.

It will give you a better throttle response due to the smaller primaries and the higher velocity through them. This is an excellent "Pro" for mileage and giddy up and go off the line.
 
If you know how to tune one, the thermoquad cannot be beat on a combination like yours. you can routinely get MPG numbers in the low 20s with a decent gear and light foot and still have 850 CFM on tap to start a fight. If you want something that doesn't require a lot of tuning and will remain ROCK solid, the old Holley 3310 750 is a great choice.
 
I think TQ is a great carb , if you can find one . I like the eddy 750 cause if he decides to change the cam and do some head work a few easy changes and the 750 will still be a good carb , 650 not so much , of course the TQ 850 will do as well . Had one on my 318 back in the day and it was great , got great gas mileage due to small primaries and when the secondaries opened it screamed , was miles ahead of the 650 AVS and the holley 750
 
Fantastic feedback on the carbs! Thank-you all!

Now you've got me really curious about this dirty old thermoquad I've got sitting on a shelf in my garage. I was gonna sell it because I've heard they are tricky to deal with. But now I'm thinking of using it, if I can find someone trustworthy to rebuild it. Unfortunately I don't trust myself with it
 
Daily driver with great throttle response, mileage available, cheap to find and recondition, Thermoquad! Draw back...hard to find jets and metering rods for tuning. I wound up buying half a dozen TQ's most of them were parts carbs I needed to get an assortment of jets and rods. I have run TQ's in the past as well as other carbs and for street manners and overall driveability they are extremely hard to beat.
 
screeminDemon said:
Fantastic feedback on the carbs! Thank-you all!

Now you've got me really curious about this dirty old thermoquad I've got sitting on a shelf in my garage. I was gonna sell it because I've heard they are tricky to deal with. But now I'm thinking of using it, if I can find someone trustworthy to rebuild it. Unfortunately I don't trust myself with it
Click to expand...

Give it a whirl, I thought the same thing, there really isn't much to rebuilding one. If I can do it anyone can.

IF you do try, there are 2 screws under the choke plate be sure and remove those before trying to separate the sections.


WHOOPS!
 
screeminDemon said:
Fantastic feedback on the carbs! Thank-you all!

Now you've got me really curious about this dirty old thermoquad I've got sitting on a shelf in my garage. I was gonna sell it because I've heard they are tricky to deal with. But now I'm thinking of using it, if I can find someone trustworthy to rebuild it. Unfortunately I don't trust myself with it
Click to expand...

Give it a whirl, I thought the same thing, there really isn't much to rebuilding one. If I can do it anyone can. Plus it will give you a better understanding of the carb. I knew nothing about them prior to doing mine, Strokerscamp convinced me. I have had them on some older cars I had when I was younger but never took the time to learn them.

IF you do try, there are 2 screws under the choke plate be sure and remove those before trying to separate the sections. Some folks have tried prying it apart with those in there=not good.
 
Here is a couple pics of the old thermQ I acquired a while ago. Badsport - I appreciate your optimism on rebuilding this sucker, I think I may give it a go. Then I need to find a real carb guru, as suggested by mbaird. I love the idea that it will get good mileage driving around, but then the size of those secondaries looks awesome for power when needed!

I believe I'm sold on the thermoquad.
 

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You should still try it on the tooker if its still on.

Those thermoquad are nice when they were set up right and not warp from the heat. I would not hassle with it now, just compromise and get a afb--eddy carb.

Since you have it already well I guess I would try it. I might even just flush the fuel bowls out by pouring fuel in the vents and shaking it upside down a few times.

What do you got to lose ? put it on, plug all the vacuum fittings, pour some fuel in and fire it up.

Unless the carb does look very dirty, hard to say by the pictures, its inside what counts. But again what harm, can't run any worst, correct?
 
screeminDemon said:
Here is a couple pics of the old thermQ I acquired a while ago. Badsport - I appreciate your optimism on rebuilding this sucker, I think I may give it a go. Then I need to find a real carb guru, as suggested by mbaird. I love the idea that it will get good mileage driving around, but then the size of those secondaries looks awesome for power when needed!

I believe I'm sold on the thermoquad.
Click to expand...

All I can say is mine performs great and it probably isn't tuned as well as it could be as I'm still learning them.

You can get a rebuild kit through NAPA that's where I got mine. I also ordered the brass floats as well, they didn't come with the kit.

Check the wells on the bottom of the phenolic body, they can come loose as they are only glued in place. Also check it for cracks and warpage.

Here is a couple of links for you.

http://www.moparnuts.com/images/stuff/Tquad2.pdf

http://www.imperialclub.com/Repair/Lit/Master/290/intro.htm

http://www.thermoquads.com/page204.html
 
dustoff440 said:
Daily driver with great throttle response, mileage available, cheap to find and recondition, Thermoquad! Draw back...hard to find jets and metering rods for tuning. I wound up buying half a dozen TQ's most of them were parts carbs I needed to get an assortment of jets and rods. I have run TQ's in the past as well as other carbs and for street manners and overall driveability they are extremely hard to beat.
Click to expand...

Actually the parts are readily available from a southern source, problem is they are WAY expensive. There is a guy who makes the metering rods, strip kits etc. the problem is you need to take out a second mortgage on your house to get them.

However he DOES have a large stock of carbs, somewhere around 150,000 on the shelf of all different kinds. I thought his prices for carbs was reasonable to what he gets for the parts.
 
The thermoquad gets a bad rap...really. It was introduced in the early 70s right when all the emission controls were comin out. The reason it got the bad rap is because the plastic body does warp...but only because of the raised temps due to all the emissions stuff. On a performance application, where temps are nice and cool, they don't have a problem. They are great performance carburetors, that had they been introduced in the muscle car era would have proven themselves to be THE carburetor to beat. ...and they still kinda did. Tons of super stock cars have won with them and still do.
 
One thing I might add is to take some photos of all 4 sides of the carb and the top, paying close attention to the linkages BEFORE you take it apart. You will find that very helpful when you put it back together.

Do your adjustments by the book in succession, do not skip one and try and go back. Each adjustment is dependent on the other.
 
LJS30 said:
Save yourself some headaches and go with the Edelbrock.
Click to expand...

As much as I'd love to argue with that, that's probably a good idea for someone with limited or beginner carburetor skills. But he already has a TQ and a kit won't cost much. Wouldn't hurt to try. That's what hot roddin is all about.
 
I thought I'd be creative and slap an Eddy on mine a couple of months ago, big mistake.. I bet it sat on there for 15 minutes before I commenced to rippin it back off. I'm not knocking Edelbrock by any means I have used them in the past with good luck, but for my application the TQ wins hands down. Idles better, runs WAY better when I have my foot on the floorboard runnin her up to 5500 or so it don't miss a beat. Even cruising down the road at 55 and I mash it, man does it come alive, and I mean right now.

Now I'm sure I could have tuned the carb a little better and made it work, but why. After all the carb is fairly new and I did have it on another chebbie smallblock in a vehicle I had, and it ran great on there. Maybe in the future if I find a good deal on some other brands I "might" try them, but for right now, naw.
 
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