Carb Recommendation

[RD_Racing]

Im looking for carb recommendation for my new SBC 406 build with tunnel ram.. I was looking at the older Holley 660 center squirters (#4224) but is there a better/newer choice that is more friendly to tuning? I prefer to buy new carbs and these 4224's new are roughly $800 each new.. Im hoping to keep the carbs “inline” which limits my choices.. With that said, will vacuum secondaries hurt performance/power? There is a local shop that specializes in modifying Quickfuel 600 carbs for tunnel rams and claims they flow 660 when they are done but they are vacuum secondaries.. Here is what they do and the cost for a pair is far less than a pair of 4224's:
CHOKE HORNS HAVE BEEN REMOVED
INSTALLED DOWNLEG BOOSTERS
TRICKED OUT FRONT METERING BLOCKS
SECONDARY METERING PLATES INSTALLED THAT GIVE YOU ADDITIONAL JETS IN THE REAR
ADJUSTABLE VACUUM SECONDARY HOUSING
IDLE AND HIGH SPEED AIR BLEEDS
4 DOOR POWER VALVE
HIGH FLOW NEEDLE AND SEATS
CLEAR SIGHT GLASSES - TO HELP WITH FUEL LEVEL ADJUSTMENTS
CAST ALUMINUM MAIN BODY AND FUEL BOWLS
POWER VALVE BLOWOUT PROTECTION
NON-STICK VITON GASKETS

Motor specs:
406, 4340 3.75 crank, 6” rods, wiseco 11.7:1, Promaxx Shocker 225cc heads, Solid roller 265/270 @ 050 (.672 lift with 1.6)

[statsystems]

I wouldn't use a VS carb if it was free.

If you are married to inline carbs you are pretty much stuck. I've posted before that I've thrown away 4224's because I couldn't give them away. Many here said they would have taken them. Maybe.

You need to call BLP or Bo Laws and talk to them. I'd be surprised if they told you a VS carb was what you needed unless the inline deal leaves you no other option.

[statsystems]

BTW, if that put a jet plate in the rear I'm not sure those carbs will still go in line.

[prairiehotrodder]

I think you could use edelbrock carbs inline. I just put a t-ram on a 540 and I used the new holley 750 track warriors. They are way out in left field for a 2x4 application and need lots of changes. The linkage for sideways mount was not to bad though and its easy to work on the carbs because the float bowls are accessible.
Brian

[F-BIRD'88]

Use 2 of the new Edelbrock 650 AVS2 carbs with the upgraded anular boosters. Very reasonable price lots of
benefits and tunability.

Or use 2 750 1407 eddies.
You are wasting your time and money with vacuum secondary holley carbs..

You can build your own 2x 750 HP double pumpers
using any 2 650-700-750 holleys as donors
upgraded with the Proform 750 hp body kits.


The Holley/Demon 750 "Street Demon" carbs are another
option.

The eddy carbs work fine and are easy to tune
They work.

Vacuum seconday holleys are for skiboats and TBuckets.
(street stuff that does not accelerate quick. )

[statsystems]

I agree with F-bird...you can buy two ProForm 750's and make a few changes yourself and be miles ahead.

Of course, they won't be inline.

[RD_Racing]

Use 2 of the new Edelbrock 650 AVS2 carbs with the upgraded anular boosters. Very reasonable price lots of
benefits and tunability.

Or use 2 750 1407 eddies.
You are wasting your time and money with vacuum secondary holley carbs..

You can build your own 2x 750 HP double pumpers
using any 2 650-700-750 holleys as donors
upgraded with the Proform 750 hp body kits.


The Holley/Demon 750 "Street Demon" carbs are another
option.

The eddy carbs work fine and are easy to tune
They work.

Vacuum seconday holleys are for skiboats and TBuckets.
(street stuff that does not accelerate quick. )

Thanks F-Bird, the AVS2 Eddys seem reasonably priced too.. Can I run them as a single feed, I see they have the option to run them as a dual feed too..

[Tuner]

Until and unless Edelbrock fixes the short booster problem in the 750 versions they should be avoided. The primary venturi in the 750 is 5/16" lower in the body than the 600 and they use the same booster cluster in both carbs. The exit of the booster venturi is 5/16" above the minor diameter of the main venturi, which locates it about 3/8" above the vena contracta, where the tail of the booster should be.

You didn't say if it will be stick or automatic. Vacuum secondary is excellent with either, but more sensitive to finding the correct spring in the vacuum servo with a stick. A pair of 1850s is good on a tunnel ram. I have been using them in pairs since before tunnel ram intakes were even available, back when cross-rams were the New Big Thing, back when 1850s were only 585 CFM.

If you local shop with the Quickfuel 600 carbs will work with you to tune them and will stand behind their work, that is probably your best option, particularly if the price is right. Get an Innovate MTX-L A/F gauge and dial them in. Option 2 is a pair of 1850s and tune them. If you are interested, I have an excellent starting recipe for 1850s on a T-Ram, I think it is already posted in a Speedtalk thread some time back.

[F-BIRD'88]

A buddy here has been running eddy 750's 1407 for over 10 years on a tunnel ram.
No issues. were not that hard to dial in (jetting) and were dyno compared to prepped proven holley double tunnel ram carbs. The holleys only made a bit more power.
The eddies run trouble free. Tuners issue is over stated. they run great.
Makes well in ECCESS of 700HP.

Althou all the edelbrock carbs can be modded for dual feed fuel inlet
It is just not necessary, especially on a tunnel ram with 2 carbs.
The fuel flow is shared by the 2 carbs. Edelbrock carbs do not like excessive fuel pressure. 5psi at the carbs is right.

The new 650 AVS2 carbs have a new advanced annular primary booster now and the secondary air valve is fully adjustable. (it is not a "vacuum secondary")


Good used 660 center squirter TR carbs are not hard to find and buy used.
Some here say they cannot give them away.
You can build your own 750 HP body versions, all you need is the 4 primary small bowls and 2 rear metering plates. and 2 750HP carb body kits.
Or just mount them sideways. You can self build better than you can buy.
You have to dial them in anyway.

[F-BIRD'88]

On the eddy carbs you can remove the choke flap if you want but do not cut
the choke horn off. It is not nessessary and it requires re calibration of the air bleeds metering. Save your self the headache.
You very unlikely wlll need larger than stock needle seats either.
The stock needle seats are big enough and you get better fuel-float control with them. Try them first.
Remember the fuel metering is shared by the 2 carbs, unlike a single carb on a high power engine. Get (or make) a proper hood scoop.

[tjs44]

Get a pair of 750 AFB max wedge carbs and rejet as they are staggered jetted.You will like them a lot.Been running a pair on my tunnel ram for years.Tom

[Geoff2]

Agree with FB88. The 750 Edel carbs are great, many in use with happy owners.

[RD_Racing]

You didn't say if it will be stick or automatic. Vacuum secondary is excellent with either, but more sensitive to finding the correct spring in the vacuum servo with a stick. A pair of 1850s is good on a tunnel ram. I have been using them in pairs since before tunnel ram intakes were even available, back when cross-rams were the New Big Thing, back when 1850s were only 585 CFM.

If you local shop with the Quickfuel 600 carbs will work with you to tune them and will stand behind their work, that is probably your best option, particularly if the price is right. Get an Innovate MTX-L A/F gauge and dial them in. Option 2 is a pair of 1850s and tune them. If you are interested, I have an excellent starting recipe for 1850s on a T-Ram, I think it is already posted in a Speedtalk thread some time back.

Its a TH350 rated for 800hp and im running a 4500 convertor (footbrake). I did find some old posts and have been reading them too

[RD_Racing]

On the eddy carbs you can remove the choke flap if you want but do not cut
the choke horn off. It is not nessessary and it requires re calibration of the air bleeds metering. Save your self the headache.
You very unlikely wlll need larger than stock needle seats either.
The stock needle seats are big enough and you get better fuel-float control with them. Try them first.
Remember the fuel metering is shared by the 2 carbs, unlike a single carb on a high power engine. Get (or make) a proper hood scoop.

Im going to try the AVS2 carbs, Summit has them on sale right now for only $288each.. I went with the 1905 manual choke and will probably end up removing the mechanism and blade after I see how they run.

[F-BIRD'88]

keep us posted on how this progresses for you. I got the feeling that those AVS2 carbs are going to be very popular.