Holley street demon on a 440

[Bobby Sixkiller]

I have been thinking of trying a new Holley street demon 750 on my440. They are similar to a thermoquad. My cam is 284d/484lift. 10.3 to 1 compression. All else pretty stock Anybody tried one with that cam.

 

[Darter6]

I've never tried one yet but have heard good things about them.Price is very competitive with the other brands.
If you do go this route let us know how thing turn out.

 

[727]

I have the 750 with the polymer bowl on my 440. Starts easy when hot or cold.

I like it and would recommend it over an Edelbrock.

 

[72RoadrunnerGTX]

I tried one recently on a mild build 400. Had several issues that bothered me enough to pull it off and go back to a Thermoquad. Accelerator pump was not working out of the box, found small gouges around the plunger lip seal and a tear in the mushroom valve, replaced both to get a functional pump. Their optional Mopar throttle pin is worthless if running stock throttle cable and brackets, had to build an adapter for the “Universal” Street Demo throttle lever and run a stock pin to regain the correct alignment/geometry for the throttle cable and throttle pressure linkages. The goggle valve would stick in its bore on cool down, first opening required a bit of force. Yes, I did re-seat the blade in the bore, didn’t help much however.

While I did eventually manage to get decent warm running performance out of it, the choke components are cheaply made with loose tolerances, made it difficult to tune for decent cold running too. Overall, IMHO, It’s not near the quality of the standard Holey products, or the original Thermoquads when new, not the same cost either. I would rate the quality as comparable to the Edlebrocks and other cheaply made “Universal” type aftermarket carbs.

Also, instructions indicate they want an aftermarket air cleaner used, possible interference with the choke linkage. Didn’t find that, but there is not much to register the stock air cleaner to the air horn other than the stud. Missing some ports as well, canister purge and idle bowl vent, should that concern anyone.

 

[Bobby Sixkiller]

I was wondering if they were Holley quality or more Edelbrock type. I think I’ll just stick to what works. 4150 and such.

 

[beanhead]

For what it's worth...'iffy' quality control seems to be a common theme now for all the Holley-owned brands unfortunately...the beloved Quick Fuel brand carb I have on loan from a good friend (new 750 street-Q un-used still in the box--he bought it 2 months ago) had a torn metering block gasket and one of the throttle plate-to-main body screws was SO damn tight the phillips slots in the screwhead got mangled getting it out. Oh and one of the little pump nozzle rubber o-ring gaskets was crumbling..that said ANY carb needs to be disassembled, checked and cleaned before use..whichever you choose, size it right and get the features you want. They can all run good when you set them up right.

 

[Darter6]

Just a little info on Edelbrock, At a show,I was talking to one of the Techs and he gave some advise. He stated the best carbs are Edelbrocks remanufactured carbs.He pointed out they are carbs that have been pulled from the assembly line for whatever reason.These carbs are then disassembled, inspected and repaired by one persons hands instead of 20.He also stated they hardly have any of the remans come back.So they are built with better care and they cost less. That was about 15 years ago. That's all I buy anymore.12 since then.Fact or fiction they are working for me.Just something I learned over the years.

 

[Joske2]

Just put 625 Street Demon on a 64 Chebbie 327 (out of the box) to replace a 500cfm Eddie AVS 2,(with a lot of tuning) and so far the eddie wins (barely).
I do have to say that its very good as is. Now we start tuning it to see which way it goes.

 

[Montclaire]

They have had some assembly issues, best bet is to watch their eBay listings for refurbished ones at a good discount.

 

[33 IMP]

Just a little info on Edelbrock, At a show,I was talking to one of the Techs and he gave some advise. He stated the best carbs are Edelbrocks remanufactured carbs.He pointed out they are carbs that have been pulled from the assembly line for whatever reason.These carbs are then disassembled, inspected and repaired by one persons hands instead of 20.He also stated they hardly have any of the remans come back.So they are built with better care and they cost less. That was about 15 years ago. That's all I buy anymore.12 since then.Fact or fiction they are working for me.Just something I learned over the years.

I had a simipar experience many years ago. Mallory, at the time (long before becoming msd umder a different name) had a somewhat poor reputation for reliability, but i heard that the remans were all looked at, and fixed. I heard of a super shops warehouse sale of remans (who remembers Super Shops?) and bought an ignition box , coil, and 250gph fuel pump, for pennies on the dollar. All three still going strong.

 

[Darter6]

When I first moved to Nevada we had a nice Super Shops in Vegas. Only a year or two then they closed up.

 

[Bobby Sixkiller]

I remember seeing super shops on Don Garlits swamp rat.

 

[Bobby Sixkiller]

 

[origcharger]

I had one on my 440 Charger, didn't hate it.
Annoying is having to buy a $30 plus dollar throttle linkage stud and an AR Engineering "high rise" throttle cable bracket in order for all that to lineup/hookup/look right.
I used a drop base Mancini air cleaner bottom without issues.
I ended up converting that 440 to a Sniper EFI and putting the Street Demon 750 on a 383