Holly or Thermoquad

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72dart_swinger

72dart_swinger

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I have a stock 360 with a mild cam in it and am in need of carb help. I have a new holly 700 dp sitting on the shelf at the house (was going to go on dads 340 but he decided against it), and I also have a thermoquad that just had a kit put in it last week. This is just going to be a street car. It is currently getting 3.73 gears and is an automatic.
 
I assume the question is which one to use?

Personally I prefer the Holley, because I have a lot of experience with them.

But others feel probably just the opposite, for the same reasons.

By your descriptions, you can't hardly go wrong. Both should work well.
 
If you can tune the Thermoquad, or are willing to learn to tune the Thermoquad, that is my vote. If you want to bolt it on and have it run reasonably well or want to have something most anyone is familiar with, go Holley. A street car as you describe it will be better served by a well tuned Thermoquad.
 
What numbers are on the T-Q?

How big is the cam?
 
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 1,600-5,800
Intake Duration at 050 inch Lift 224
Exhaust Duration at 050 inch Lift 230
Duration at 050 inch Lift 224 int./230 exh.
Advertised Intake Duration 268
Advertised Exhaust Duration 280
Advertised Duration 268 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.477 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.480 in.

T-Q has the smaller of the two primary sizes the # on the base plate i dont know off the top of my head but it starts with a 9***
 
Hum, ethier would work, as stated above, it's a personal choice from here. With the auto trans, i think I'd go for the T-Q at this point. Check out thermoquads.com (http://thermoquads.com/) for a strip kit. ( jets) to help tune it up.

Oh, many T-Q's start with a 9.:-D

How many ports (Vacuum ports) are on the front of the carb?

Reason I ask is that a smogger T-Q would need some work to work well on a non smog application. When you have the time to check the number, go to the T-Q site and read up on it. The site owner, David, is a striaght up guy that does some realllly good work, stock or modified.
 
Thats a nice little cam my buddy runs one in his 318 with good results..as for which carb if its a street car with an auto trans. i'd go with a holley 750 vacuum secondaries over the 700 d.p. as for the thermobog i'd never run or trust a "plastic" carb....
 
Good thing it isn't plastic. And since he has not a VC carb, the choices between the Dp and a T-Q, I'd run the T-Q with the smallish cam.

The resin body is known to crack or wrap. To avoid cracking the fuel bowl, do not over tighten it.
To avoid warping it, tighten it up evenly apon assembly and installation. Also avoid over heating the engine for sure. Excess heat is a bad thing for these carbs.

The term "Thermobog" is so coined by those whom not have an idea on how to tune the carb.
 
i'd go with the holley unless you have the skills to tune the thermoquad, they're a great carb. once they're set up right but theres not tons of people around who actually know how to set them up. So i'd say probably go with the holley
 
I believe that the T-Q is a smogger, the thermoquad web site mentions some with out the idle screw. Mine only has the long fast idle screw, that leads me to believe that it was one of the lean burn carbs.
 
I havn't ever tuned a T-Q so I guess I am leaning towards the holly, how hard are they to tune, and would the dp cause the motor to run too rich
 
Ahhh, yea, lean burn carbs will have to be modified. It would lack the vacuum port for the distibutor. There should be 2 screws for idle enrichment trimming on the base plate. Not all T-Q's have them.

the fast idle screw is on the side of the carb (Drivers) along with the screw for when the choke is active.

Running the DP isn't a problem. In order to fix the running rich problem would be the same for any carb, you'll need a jet kit from Holley. Also purchase a Holley screwdriver made for the jets. Nice little tool that'll just help keep the jets in excellent condition.

74scamp360's mention of the T-Q is, IMO, overly rated in scare. While a T-Q can be a pain to set up, it's more in the area of intail set up when building the carb, not so much when it's on top and running. Once it's on and running, it's like anyother carb really. Just a pain to change jets.
 
Sounds like I will be using the holly if the lean burn will need mods. Anyway any tips for baseline jetting? and do i need to get some of the blue reusable gaskets (fuel bowl and metering block)? Or should I try and sell the Double pumper, it has only been run for about 30 min, and get a vacuum secondary carb like a eddy performer
 
Use what ya got! The blue reuseable gaskets are excellent to have. My mention to use the T-Q is my choice. You can get that holley working real good, no problem. You might not be able to floor it right away, but you'll learn that as you go.

Start with whatever jets are in the carb now and work it from there. You'll be fine. Don't worry.
 
The Holley is probably best for balls out performance only because the thermoquads just dont have the tuning support. Parts are tough to find and expensive. Demon Sizzler has some stuff on his site. Thermoquads are great carburetors. But they have a learning curve to tune them. Holleys do as well, but have much more support. I guess the biggest reason I like the thermoquad is because they are different. I like to hear "what thell is that thing?" when I open the hood. LOL
 
StrokerScamp said:
The Holley is probably best for balls out performance only because the thermoquads just dont have the tuning support. Parts are tough to find and expensive. Demon Sizzler has some stuff on his site. Thermoquads are great carburetors. But they have a learning curve to tune them. Holleys do as well, but have much more support. I guess the biggest reason I like the thermoquad is because they are different
Click to expand...
. How true that is. For a factory carb, there very good. Remember those words, factory and very good. Not aftermarket and great. IMO that is.

I like to hear "what thell is that thing?" when I open the hood. LOL
Click to expand...
He he he, Me 2! Funny stuff.
 
Does anyone know what the factory jets in it are? I tried to search but came up with nothing. I am just trying to avoid buying the complete jet kit from the 60's to the 90's if I can and was hoping that the factory jets fell in the range of one of jegs kits (70-80) (80-90) (90-100) just trying to save a little if I can. Working on cars is tough on a college kid's budget.
 
The Holey jet kit? You can gettem in a box from 66 - 99 in one shot.
 
I like to hear "what thell is that thing?" when I open the hood. LOL

Yep, the ford and chevy boys talk about my carb all the time, they can't see how something that big can work on a small block, I just pat them on the back and say Mopar boys Mopar.
 
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