Carburetors for STR-12 Manifold

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DC 340

DC 340

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I am building an Edelbrock STR-12 manifold intake system here:

IMG_20231014_175638.jpg


Wanting new carburetors for the thing. I'll be working fuel line and linkage for the rest of my life LOL. I am seriously looking at the Edelbrock VRS-4150 series, #1306 (650 cfm). I need two. Any advice? A link:

www.edelbrock.com

VRS-4150 Carburetor 650 CFM #1306

Edelbrock VRS-4150 Race & Performance Carburetor #1306 is race ready with four circuit billet metering blocks for full tuning capability and street friendly with a universal fit throttle arm, vacuum fittings and provisions for a TPS sensor.
www.edelbrock.com www.edelbrock.com

Thanks.
 
Impossible to help you without knowing about your engine size and how built your or stock it is. Streetcar? race car? Or both?
 
Street, S/S, 600-650 cfm
Race, 750 cfm

Manufacturer, model and style, your call.
 
I've heard stories of the lid breaking from backfires. I would research that. I have seen new linkage in reproduction but I don't remember where. Beautiful setup, I will follow your progress.
 
I’ve seen home built spring assisted backfire relief valves built for them before. Modifying one to outfit it with a burst panel or supercharger backfire relief with light springs probably isn’t a bad idea.
 
67Dart273 said:
Uh, doesn't this really depend on the engine build?
Click to expand...
Yes it does, I agree. I have a few engines it may go on. My 389 c.i. 340 stroker is what I was thinking. But really, just wanting to build a versatile small block setup. The VRS-4150 has all the vacuum ports/PCV ports for street which is important to me.
 
Maybe something in the Holley Brawler series could fit the bill at a lower cost? Looks like they have some that are street oriented and still have a lot of adjustability with bleeds and such. My main thought is whatever you choose, you have to get the pump shot right for that large plenum. Oh, and i do think the 650 is right in the ballpark for anything with that manifold over 340''.
 
there's a lot going on there in the "good" column: 4 corner idle, pcv/vacuum provisions, down leg boosters, fuel inlets, float level windows, tuning parts, but i guess the question is if you want to run dual double pumpers on something that's not a race car?
 
67Dart273 said:
Uh, doesn't this really depend on the engine build?
Click to expand...
Normally, yes, this is why I answered what I did.

Here is food for thought. If 318 will run can put 2, 600 Edelbrocks on a in line dual quad on top of a 318…… I’m sure a 340 will handle it just fine. I’m also sure, a stroker 340 to say, 420_ish area will do just fine.

If I was racing with this intake and it’s a 340 to a 434, it would be twin 750’s.
 
I've been running this on the street for 15 years now (340+.030). I'd be glad to correspond with you about an STR-12 on the street. It is set up with 2 500 Edelbrock performers (AFB), but I think if I were replacing them today I'd use 500cfm AVS2s. I'll send you a PM. My original lid was cracked and repaired twice but someone put me on to a fix that I can share that resulted in my never having the backfire issue. I can also send detailed pics of fuel lines and linkage. Right now my manifold is off (for the first time in 15 years) for pushrod replacement, so it's a good time to ask questions and request pictures as I reassemble it over the next week.


340 11-06 b.JPG


340 11-06 k.JPG
 
If somebody wants to really hog wild with one of these, mine came with a lid to mount a BDS blower on it that I am very sure I will never use!!!
 
I install two spring loaded burst plates on my bigger manifolds (tunnel ram, big single plane etc). The need to be adequately sized unlike some of the postage stamp sized units contained in a spacer.

If it was me I would be running something with annular boosters and a relatively lean transition/cruise AFR and a tad rich idle AFR. It seems to help .

Not a fan of the Brawler carbs OOTB.
 
Jeremiah said:
I install two spring loaded burst plates on my bigger manifolds (tunnel ram, big single plane etc). The need to be adequately sized unlike some of the postage stamp sized units contained in a spacer.

If it was me I would be running something with annular boosters and a relatively lean transition/cruise AFR and a tad rich idle AFR. It seems to help .

Not a fan of the Brawler carbs OOTB.
Click to expand...


Pay attention to that last sentence. Brawlers out of the box are stupid fat. They need work. A lot of work.
 
Garrett Ellison said:
Backfire relief valve
Nitrous Express (NX) 15462 Nitrous Express Manifold Pressure Release Plates | Summit Racing
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Cool! That would be a big decision though to mount. Your post lead me to this:

www.summitracing.com

Nitrous Express (NX) 15461 Nitrous Express Manifold Pressure Release Plates | Summit Racing

Free Shipping - Nitrous Express Manifold Pressure Release Plates with qualifying orders of $109. Shop Manifold Burst Panels at Summit Racing.
www.summitracing.com www.summitracing.com

That might work well without manifold mod but expensive X 2 for me. But it is a money pit I am working on. I understand. Thinking... In the spirit of money pit, I am still leaning towards the Edelbrock VRS-4150 as I want to try something different.
 
Garrett Ellison said:
Backfire relief valve
Nitrous Express (NX) 15462 Nitrous Express Manifold Pressure Release Plates | Summit Racing
Click to expand...

CFE used to make a similar model as this one:

www.summitracing.com

Nitrous Outlet 00-49003 Nitrous Outlet Pressure Relief Panels | Summit Racing

Free Shipping - Nitrous Outlet Pressure Relief Panels with qualifying orders of $109. Shop Manifold Burst Panels at Summit Racing.
www.summitracing.com www.summitracing.com

This size works well, especially one on each side of the plenum on a t-ram.

That said, many people have run large plenum manifolds and done nothing. I like safety precautions that protect my equipment so a few hundo seems reasonable.
 
The whole point of the STR manifolds was to get the runner length of a tunnel ram, under the hood (STR = Street Tunnel Ram) In my Dart I couldn't put any carb spacer in and it was a struggle to find an air cleaner with enough perimeter length to use a filter element that was only about an inch tall and still have enough filter surface. That blow off plate that goes under the carb wouldn't fit for sure! There's plenty of room for the spring loaded nitrous plates, though...
 
DC 340 said:
I am building an Edelbrock STR-12 manifold intake system here:

View attachment 1716163619

Wanting new carburetors for the thing. I'll be working fuel line and linkage for the rest of my life LOL. I am seriously looking at the Edelbrock VRS-4150 series, #1306 (650 cfm). I need two. Any advice? A link:

[/URL]

Thanks.
Click to expand...
New street build and new carbs. For dual 4 barrel, Edelbrock tunes the AVS2 500 carbs. That is what I would be looking at.
With the large plenum you will need a strong accelerator pump shot. You can use a number drill to increase the pump squirter ID to let more fuel out quicker.
I would be inclined to talk to Dan at The Carburetor Shop in Minnesota. They can probably modify the accelerator pump shots to what you need.
 
Thanks all for your input. This is what I already did. : ) I ordered two Edelbrock VRS-4150 series #1307 rated 750 cfm. The 750 comes with annular boosters as the 650 does not. I think they will work for me.

VRS-4150 Carburetor 750 CFM #1307

Will post pics when they get here.
 
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