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Holley 650 jetting help
#1
Hello! As some of you might remember, my neighbour gave me an old Holley 650 double pumper he had laying around.


I test fired the engine with the carb and it ran good. Better idle than my old edelbrock, and waaay better throttle response. (I think my old edel was faulty as well)

Anyhow, i ordered a rebuild kit and started pulling it apart. And i noticed the carburetor is missing its jets whistling
No clue how it could run so good without jets...

But now since i never played around with carbs so much, i dont know where to start with jets.
I thought since it ran pretty good i would buy one size over and one size under what was already in it. But thats difficult since it didnt have any.

So Im consulting the experts here, where do you think should start?

0.30 over 351cc
Forged flat top pistons
Elgin street/strip cam. 512/538 lift
Ported 2v heads
Holley street dominator intake
Flowtech full lenght headers and dual 3" exhaust
Thunder HEI distributor
3.50 gears.

I know this probably very hard to do, but all recommendations are welcome. Or maybe someone atleast know what stock jets are in a 650 holley.

Thanks in advance Smile

1972 Mercury Cougar XR-7 2dr hardtop
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#2
Odmark;284236 Wrote:Hello! As some of you might remember, my neighbour gave me an old Holley 650 double pumper he had laying around.


I test fired the engine with the carb and it ran good. Better idle than my old edelbrock, and waaay better throttle response. (I think my old edel was faulty as well)

Anyhow, i ordered a rebuild kit and started pulling it apart. And i noticed the carburetor is missing its jets whistling
No clue how it could run so good without jets...

But now since i never played around with carbs so much, i dont know where to start with jets.
I thought since it ran pretty good i would buy one size over and one size under what was already in it. But thats difficult since it didnt have any.

So Im consulting the experts here, where do you think should start?

0.30 over 351cc
Forged flat top pistons
Elgin street/strip cam. 512/538 lift
Ported 2v heads
Holley street dominator intake
Flowtech full lenght headers and dual 3" exhaust
Thunder HEI distributor
3.50 gears.

I know this probably very hard to do, but all recommendations are welcome. Or maybe someone atleast know what stock jets are in a 650 holley.

Thanks in advance Smile

What is the list number of the carb?

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
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#3
71 front and 73 rear is a good place to start.
  Reply
#4
TommyK: the list number is 6711

Barnett: okay thanks :thumb

1972 Mercury Cougar XR-7 2dr hardtop
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#5
I was going to say 72 primaries and 74 secondaries is where I would start, but Barnett's numbers are equally good

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#6
That is a spreadbore carb?

If so it will want a small primary jet, say 62-65 and a relatively large secondary jet say 80ish?

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
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#7
barnett468;284240 Wrote:71 front and 73 rear is a good place to start.

That's clever. Smile

The holley street avenger 670cfm comes with 65 main and 68 secondary. This is probably a good place to start.

I run 64 mains in my Jeep with a Truck Avenger 670 at Phoenix altitudes. I was able to run 61's and get the darn thing up to 13000 feet.

It's a bit worrisome that there were no jets.

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
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#8
will e;284254 Wrote:
barnett468;284240 Wrote:71 front and 73 rear is a good place to start.

That's clever. Smile

The holley street avenger 670cfm comes with 65 main and 68 secondary. This is probably a good place to start.

I run 64 mains in my Jeep with a Truck Avenger 670 at Phoenix altitudes. I was able to run 61's and get the darn thing up to 13000 feet.

It's a bit worrisome that there were no jets.

the street avengers are notoriously lean and he would likely melt his engine running a 65 on a street avenger.
  Reply
#9
That's a 4165 carburetor that was designed for emissions and has no replaceable jets.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#10
that would explain why it has no jets.
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