Carb for 408

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zsn0w

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I'm doing the final parts selection for a 408 build I've been planning for awhile, and I'm wondering about my choice of carb. This is going to be a street engine that I want to do well at low to mid rpm. I'm more concerned with keeping performance there good than I am with maximizing the top-end. I was originally thinking I was going to go with a Holley 750 CFM ultra double pumper, but now I'm wondering if a different carb like an Edelbrock 800 CFM AVS2 or a 750 CFM street demon would be better. Open to any suggestions at all, these are just the ones that have caught my eye so far. This is also going to be going into a B-body, I've just had much more engagement about engine questions over here in the past than on FBBO. Thanks!
 
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Go on Facebook and look up dominicthumper and get him to do a carb for you.

Or mark Whitener.

Or BLP. Or Braswell. Or Dale Cubic. Or Dambest (I forget his name).

If you buy a carb from one of theses guys you most likely won't even change a jet. If you buy an off the shelf carb, you WILL have to tune it. It's a pay now, pay later deal.
 
Well, my car is 75% race and 25% street...so my opinion is slanted that way, but with that said I would stick with the Holley 750dp. It will still drive well on the street AND make more power than the others if needed.
 
Go on Facebook and look up dominicthumper and get him to do a carb for you.

Or mark Whitener.

Or BLP. Or Braswell. Or Dale Cubic. Or Dambest (I forget his name).

If you buy a carb from one of theses guys you most likely won't even change a jet. If you buy an off the shelf carb, you WILL have to tune it. It's a pay now, pay later deal.
Braswell is SERIOUSLY overpriced....Just my opinion as someone who likes to keep a few dollars for other things.....
 
Braswell is SERIOUSLY overpriced....Just my opinion as someone who likes to keep a few dollars for other things.....


Ever use one? I have. And BLP. And a Cubic carb. Worth every penny. Every time. Just like an off the shelf cam, and off the shelf carb is the same.

The real issue is most guys bolt the carb on and leave it and the ***** about how the idle sucks, no fuel mileage, fouled plugs and all the rest.

You can either pay up front, do the tuning yourself and spend the time to do it, or buy off the shelf **** and live with it.
 
I have had great performance with AED carbs, give them a call.
 
So you want a carburetor recommendation but ALL you GIVE is a cubic inch displacement. LMAO
 
I had Pro System build on for me.
Stipulating mostly street with some strip time. It came out around 900+ com IIRC ..actual cam will vary depending who and how they flow them. Havent dives the car yet but it fired right up and idled well.
 
Get a holley based carb with replaceable bleeds and restrictions, also buy an AFR gauge set up and have at it. You will learn a lot and know how to tune when you are done. All the new carbs have the fancy metering blocks with way to much emulsion in them and run pig rich on a street car OOTB.
Carb Tunning
The other option is pay someone for their knowledge.
 
So you want a carburetor recommendation but ALL you GIVE is a cubic inch displacement. LMAO
I CAN give you any other info you want if you ASK me for what you need rather than making fun. I obviously do not know what all info you want to know to be able to make a recommendation. It’s going to be a 408 with edelbrock performer rpm heads and a Hughes 2832 hydraulic flat tappet cam. That’s .565 and .571 lift with the 1.6 rockers I’m going to be using. Hughes Engines Around 10:1 CR. Ld340 intake. Headers.
 
I CAN give you any other info you want if you ASK me for what you need rather than making fun. I obviously do not know what all info you want to know to be able to make a recommendation. It’s going to be a 408 with edelbrock performer rpm heads and a Hughes 2832 hydraulic flat tappet cam. That’s .565 and .571 lift with the 1.6 rockers I’m going to be using. Hughes Engines Around 10:1 CR. Ld340 intake. Headers.

Nobody's makin fun. You can have a stock stroke 340 that needs a 1050 dominator if it has all the right stuff, much less a 408. Are the heads as is or will they be ported? Head flow numbers would be great. Car weight, converter type and gear and rear tire size all play a role.

In order to give a good recommendation, we need it ALL. Why should we have to ASK when this is something YOU need? If you want a good and accurate answer, you need to give good and accurate information. Come on guy, you know how this works. Nobody's tryin to be funny here. 'Cept you leaving out important information.
 
I CAN give you any other info you want if you ASK me for what you need rather than making fun. I obviously do not know what all info you want to know to be able to make a recommendation. It’s going to be a 408 with edelbrock performer rpm heads and a Hughes 2832 hydraulic flat tappet cam. That’s .565 and .571 lift with the 1.6 rockers I’m going to be using. Hughes Engines Around 10:1 CR. Ld340 intake. Headers.


If you are going to use a dual plane intake you need a bigger carb. A single plane can use a smaller carb.

That's why I said spend the money up front and get a carb for exactly what you are doing.
 
With the street demon I can attest to excellent idle, throtlle response, crispness, acceleration, wot etc on the street in general (and strip after exploring the limits of tuning) You will have to tune it period, even just for the street. But it is cheap, just buy the tuning kit and work methodically on tuning it and you likely will be set. Or go with one of the off the shelf mid priced Holley (or variants) but expect to tune it for you setup. Or go all out like others have advised, and likely not have to mess with it much at all. (I have no experience with those so have nothing to say pro/con) Others here far more knowledgeable. I have run the entry priced 750 street demon and now have a mid priced AED 750 on my stroker setup and have had to tune for my setup on my own. You will need to tune either route, maybe a little, maybe quite a bit on the first two options.
 
With the street demon I can attest to excellent idle, throtlle response, crispness, acceleration, wot etc on the street in general (and strip after exploring the limits of tuning) You will have to tune it period, even just for the street. But it is cheap, just buy the tuning kit and work methodically on tuning it and you likely will be set. Or go with one of the off the shelf mid priced Holley (or variants) but expect to tune it for you setup. Or go all out like others have advised, and likely not have to mess with it much at all. (I have no experience with those so have nothing to say pro/con) Others here far more knowledgeable. I have run the entry priced 750 street demon and now have a mid priced AED 750 on my stroker setup and have had to tune for my setup on my own. You will need to tune either route, maybe a little, maybe quite a bit on the first two options.

So where are you with your tuning? Have you done any more since you changed to the quicker opening power valve?

Everyone should read that thread.
 
I’ve got a 750cfm street demon I pulled off my 408 blueprint engine if your interested in a slightly used carb. Dustin
 
So where are you with your tuning? Have you done any more since you changed to the quicker opening power valve?

Everyone should read that thread.
Its on hold at the moment, hopefully will be back at it within a week or so. I was having a tip in, off idle hesitation afterwards (before the boosters kicked in) with the leaner primary jet change along with installing the 10.5 PV. Had to go through what I may have altered that might cause that issue. Determined that I somehow changed the secondary butterfly opening for idle, so have reset that based on research. Just haven't had it out for testing. It's been in the mid 90's for over a week, so I've just been soaking in the pool (and beer) It's about all I've been doing!
 
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I ran 9.80’s with a newer style 750 Holley on my 408. I loved that carb so much that I boxed it up and stuck it on my shelf when I switched to alcohol. Just in case. Lol
 
As far as cfm is concerned with the CID and cam known, 750 cfm is right about what you need dead nutz on.

Now what carb you want is another story. I truly believe that IF you yourself are going to tune the carb, then you should decide on what manufacturer it is going to be. Be comfortable in what your using. Don’t listen to a soul. Use what YOU want and feel good about tuning. Because for a street vehicle, any HP or torque difference between the various carb manufacturers and styles is slight and only visible on the dyno or track at the top end. Where your rarely driving.
 
I had Pro System build on for me.
Stipulating mostly street with some strip time. It came out around 900+ com IIRC ..actual cam will vary depending who and how they flow them. Havent dives the car yet but it fired right up and idled well.

Holy **** !!! New phone...******* Spell Check!
 
Thx...

I spent the last several days tuning the 750 VS on my 5.9 to get rid of a burble at low rpm cruise ... Once you get the car running there will be a learning curve for the total tune for most any carb you buy.
I am hoping the 800$ + Pro system carb doesn’t take as much tweaking as the off the shelf Quick Fuel 750 VS has taken so far ! It is coming along though... GET A WIDEBAND!
it will save your sanity!
 
I run a 800 AVS carb on my 410 stroker and it is awsome. 22mpg with 3.91 gears on a run. Still runs 11.4 qtrs. I think a new AVS with the new boosters would be even better, but personally I would go multi port EFI before that but that is only me!
 
I'm running a Edelbrock Thunder 800 on my 408. All I had to do was set the idle and idle mixture. I paid $100 for a tuning kit with jets and rods. When we ran it on the chassis dyno the AFR was right where it needed to be so I sent the kit back! I have no complaints with the carb at all.

Edelbrock Thunder Series AVS Carburetors 1812

edl-1812_w.jpg
 
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