Holley XP vs Mighty Demon

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Heywodja

Heywodja

The Heartbeat Stops Here
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What’s y’all’s opinion for or against either one of these carbs.

TIA
 
With all the information available on the internet on the Holley site and you cannot give part numbers or links?
 
My car always runs better with a Demon. I run the 3 hole blocks at .024/.025/.026 with a .031 MAB for a predictable flat fuel curve. The downleg step boosters atomize the fuel better IMO.
 
What is the intended use of the car? And what size carb/engine and intake design?
 
I am putting a stroker 427 small block Chevy into a 58 Chevy truck 10.0:1 compression.
540 ish hp and 540 ish torque at the crank.
Truck weighs approx 3350
Automatic trans 4L80E 2800 stall

Hydraulic Roller Cam - .577 Intake / .577 Exhaust Lift and 240 Intake / 248 Exhaust Duration @ .050 - 112° LSA.

Aluminum heads
64cc chamber
2.08" intake/1.60" exhaust valves
220cc intake/67cc exhaust runners

This will be a street truck, I am gonna say no track use intended but ya never know.
 
Heywodja said:
What’s y’all’s opinion for or against either one of these carbs.

TIA
Click to expand...

Neither. There are far better choices out there than those two.

BLP
ATM
APD
AED

I know the first two offer builders kits for sure and I’m pretty sure the other two do as well.
 
I had a Mighty Demon 750 on a 425 rwhp solid cam 440. It was jetted close ootb. Jet up on the secondary and all set. I didn't have to mess with that carb EVER. You can add a bigger carb with an open plenum. And if it's truly street only consider a vacuum secondary carb.My 2 cents....
 
You could run a Dominator on that. I like BLP products.
 
Or dual quads....

20231124_123909.jpg
 
I have no experience with a mighty demon, so I can’t compare the two. But the few Holley XPs I’ve tuned have been wonderful. The PCVRs are drilled and jetted, all of the air bleeds are replaceable, and the emulsion system is drilled and jetted. And they have an adjustable idle air bypass. Excellent street/strip carburetors.
 
I also have a Holley XP 950 on my 528 drag car. I couldn't tell you anything about streetability but it does have all the bleeds and pvcr drilled and tapped . A very nice piece. They are not cheap, approaching Dominator pricing.
 
I would go with whichever one gave me the most adjustability. Thanks for not answering my question.
 
I am looking at an Xp750 or a mighty demon 750. I just googled the first 750 Xp I saw.

They generally have the same intended use, and seem to have a decent amount of aftermarket support.

At this point I am not considering vacuum secondaries.

I was merely seeking opinions on the merits of either unit or lack there of.

Thanks
 
I just bought two ATM builders kit carbs today. If you are not up for doing a builders kit, call them and have them hook you up.

I talked to Angela. She will make sure you get what you need.

I asked for an oddball sizing and it wasn’t an issue. ATM is where I’d go.
 
If you don't get one from Dominic[Thumper Carbs], try Lightning Carbs on FB Mark Whitner is very good.
 
Awesome sauce everyone! I really appreciate the heads up, I am grateful
 
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