Anyone running the Holley 390 cfm carb?

[JeeperChris]

I'm planning for an Offenhauser manifold and Holley 390 cfm carb right after Winter so I would love to hear from anyone that is currently running this carb or has run it in the past. What is your review of it? How easy/hard was the linkage setup? ...etc. Any info you care to share about it.

Thanks!

...and if anyone has one laying around they don't need anymore...

 

[JeeperChris]

So I got a model 8007 390 cfm holley carb. I'm hoping to make this mod in the Spring time with an Offy 6257 Dual Port manifold.

This should be fun.

 

[gert]

Dang sorry I just saw your thread, I am running a Holley 600 4 barrel and have been surprised at how well it runs, (your 2barrel runs the same primary’s as my 4 barrel) I don’t even have the choke on it now since it will crank first hit without it,

One thing I would suggest on your set up would be to get the Percy adjust a jet so you don’t have to pull the fuel bowl off anymore you simple turn the screw on top of the Percy fuel block to change your air fuel ratio

I love having an electric pump with my carb so when any fuel evaporates it fills the fuel bowls back up before I crank it

The linkage i can’t help you with tho sorry


Sent from my iPhone using Tapatalk

 

[JeeperChris]

Dang sorry I just saw your thread, I am running a Holley 600 4 barrel and have been surprised at how well it runs, (your 2barrel runs the same primary’s as my 4 barrel) I don’t even have the choke on it now since it will crank first hit without it,

One thing I would suggest on your set up would be to get the Percy adjust a jet so you don’t have to pull the fuel bowl off anymore you simple turn the screw on top of the Percy fuel block to change your air fuel ratio

I love having an electric pump with my carb so when any fuel evaporates it fills the fuel bowls back up before I crank it

The linkage i can’t help you with tho sorry


Sent from my iPhone using Tapatalk

Thanks, that's some good stuff to think about. I remember those adjustable jet metering blocks from the late 80's when I was playing with a '68 Chevelle. Never tried one but I saw them around.
It'll be spring time before I put the Holley on the Jeep. Going to rebuild it right and get the Offy manifold for it, just got to get through the winter first...

 

[gert]

Thanks, that's some good stuff to think about. I remember those adjustable jet metering blocks from the late 80's when I was playing with a '68 Chevelle. Never tried one but I saw them around.

It'll be spring time before I put the Holley on the Jeep. Going to rebuild it right and get the Offy manifold for it, just got to get through the winter first...

Great project, it’s raining a bunch here and my feet keep getting wet so enjoy winter


Sent from my iPhone using Tapatalk

 

[JeeperChris]

New twist to this normally aspirated plot....

Just won a Barry Grant Road Demon Jr VS 525 cfm carb on ebay.

Now, before anyone says "That 4 barrel is too big for that motor..." please remember that the 2100 which seems to be one of the best 2 barrels is 500 cfm so these primaries are only 262-ish cfm so this should do quite well for the AMC 258 i6 / 4.2l engine.

So between this and the Holley 390 I should be able to get that motor to purr, and then just sell the other carb.

I love induction stuff so this is what I call having fun!

 

[JeeperChris]

Sent from my iPhone using Tapatalk

 

[gert]

Lol awesome those Barry grants are pretty cool


Sent from my iPhone using Tapatalk

 

[JeeperChris]

Lol awesome those Barry grants are pretty cool


Sent from my iPhone using Tapatalk

My line of thinking is that if the AMC 258 i6 / 4.2l can handle a 500 cfm 2100, then a 525 shouldn't be too far off the correct track. The 390 on the other hand would be under-carbing it which would not be a bad thing since I doubt I'll ever have it spinning at redline anyway, but the fact that the Demon is a performance carb should also mean that it will meter better than a standard Holley, so it should be the better choice.

We shall see!

I worked at a carb shop when I was young and always loved it there and wanted to have my own shop.

 

[gert]

My line of thinking is that if the AMC 258 i6 / 4.2l can handle a 500 cfm 2100, then a 525 shouldn't be too far off the correct track. The 390 on the other hand would be under-carbing it which would not be a bad thing since I doubt I'll ever have it spinning at redline anyway, but the fact that the Demon is a performance carb should also mean that it will meter better than a standard Holley, so it should be the better choice.



We shall see!



I worked at a carb shop when I was young and always loved it there and wanted to have my own shop.

The AMC 258 i6 / 4.2l originally came with the BBD which is a pretty small carb, going with the bigger carbs will help horse power but I’m not sure what it will do to your torque curve, the good thing with the Barry 4 barrel is that it’s 525 divided by 4 so that’s good for drivablity


Sent from my iPhone using Tapatalk

 

[JeeperChris]

The AMC 258 i6 / 4.2l originally came with the BBD which is a pretty small carb, going with the bigger carbs will help horse power but I’m not sure what it will do to your torque curve, the good thing with the Barry 4 barrel is that it’s 525 divided by 4 so that’s good for drivablity


Sent from my iPhone using Tapatalk

So I jumped on a website to calculate the cfm needed for the AMC 258 i6 / 4.2l , just for fun. I said 80% volumetric efficiency and top RPM of 5000 which gave me 298 cfm for the 80% VE and 373 cfm at 100% VE.

The primaries on the Demon are around AMC 258 i6 / 4.2l cfm (slightly smaller bores than the secondaries) and on the Holley about 195 cfm (I think the bore size is closer to the same). Either carb would need a slight bit of secondary opening to reach my estimated 80% guestimated VE. I'm predicting fast and smooth with the Holley and a little more power with the Demon (as you said) but both very close.

And even though in the picture of the Demon it shows annular discharge venturi on the secondaries, the primaries are still non-annular just like the Holley.

This is really going to be fun.

 

[JeeperChris]

So, the Demon 525 cfm got here last night. Just had some time to take a good look at it. It's AWESOME!!! Annular discharge venturis on the primaries but not the secondaries which I thought was kinda odd, I mean I know it doesn't really need them on the secondaries but it's already a 'built' carb, so why not... This is the one going on the Jeep, the Holley can sit in a corner for a while. The add from when I bought it said it was rebuilt and it's sure sparkly clean all over. There will be lots of pictures when I get to the install.